Kv6 new thermostat leaks?
 

Good morning, gentlemen.
When I fixed my fuel leak, I also replaced my thermostat because it was cracked and leaking.
I did install the new thermostat from dmgrs.
I followed rave procedure for coolant purge.

Yesterday morning , I saw a spot of coolant on the ground.
I checked the engine compartment and to my surprise, there was coolant under the thermostat.
I wondered if I had incorrectly refit the new thermostat . So , I started the operation again.
When I finished the job, I drove with the vehicle, the thermostat works well. I checked the thermostat on the way home and there were no leaks.

Today, I didn't use the vehicle, I inspected the engine compartment this morning and no trace of coolant.
But tonight, I wanted to take the vehicle out and there was coolant on the ground and under the thermostat.
How could the thermostat leak when I did not use the vehicle? This morning everything was clean, I don't understand .
Do you have an idea?
Thank you. ( I specify that I used the keyhole method)

Hello there, sorry to hear of the bother you're having!
This is usually down to a bit of crud on the O Ring sealing surface in the cylinder block - it can be very hard to clean up / see from all angles, and all it takes is a bit of detritus or pitting and you'll find you get a very annoying intermittent leak.

I'd inspect the mounting hole closely with a mirror to help you see all around it - if you have pitting it can be resolved by carefully refinishing the metal and then using a slightly larger O Ring (which we will of course supply free of charge).

Keep us posted with how you get on - we don't always see posts on here, but you can email us at [email protected] if I can help anymore. :)

Thanks you. I've do the job twice but it leaking again.
Is it a O rings's problem?

By the way, the coolant temperature hardly reaches 80 ° and 85 in city. Is this an original mg rover thermostat? with the old thermostat, the temperature was around 90°. The sensor is new.

Hello Brahim,

Sorry if I'm repeating questions that I've already asked you but ...

• Did you renew all four 'O' rings?
• After assembly did you remember to move the serrated clips on the straight pipe fully outwards?

Don't attempt to fit a larger 'O' ring to the thermostat housing. You will break it (I tried this as part of my thorough investigation of the cause of the leaks).

80 - 85 degrees is much too cool. Either the thermostat is faulty or it's not rated at 88 degrees. A genuine MG Rover thermostat is your best bet.

Simon

Hello Simon, yes i used the new o rings and i moved the serrated clips on the straight pipe fully.
Where can i find an original thermostat ? It is bad to drive with this thermostat ?
Thanks you.

Hi shuriken,

I also fitted a new thermostat in November last year (also from dmgrs).
I also found my thermostat to be operating around 80-82°c when driving and in stop start traffic to be around 85°c.

It should be the 90°c area.

Mine has been like this now for over 2,000 miles. I personally see it as a problem, but it can wait a little while before I spend that amount of money in the hope the part works as intended. To my knowledge it may just use slightly more fuel due to the cooler running temperature.(I'm also probably kidding myself here, but if it's running cooler, it's going to take a lot more for it to overheat).

As towards the leak, you say you have checked the serrated clips are pushed as far to the ends of that straight pipe as possible. Other than ensuring the mating faces on the block are perfectly clean. I could only assume it is a fault with the thermostat? Or a hose.

It could be a faulty thermostat, seeing how it opens too early, as does mine. It's possible there could be an hairline fracture in the plastic housing.

These people are X-Part agents and they post worldwide. I bought mine from them.

Use the official method of removing the plastic manifold chamber and one of the aluminium inlet manifolds for full access and a reliable result. Remove the fixing screw and carefully lever only under the bracket. Don't use the hose connections to remove or refit the parts. Lubricate and renew all 'O' rings, available separately, part no. CDU3858. Tighten the fixing screw to the specified torque. Move the serrated clips fully outwards and squeeze them tight. Follow the official refilling and bleeding procedure involving raising the expansion tank (you did do this before didn't you?).
Yes. Your fuel consumption will be high and the oil won't reach the optimum temperature which will hasten engine wear.

Simon

Have a look at Wes sale collection he as two of the stats for sale with the stabilising lugs on. also use a little red rubber grease when fitting the stat.

https://the75andztclub.co.uk/forum/s...d.php?t=312720

:wot:

Definitely buy one of those Brahim. The three stabilising lugs are a very sensible modification, or "upgrade" as would be said here on the forum! ;)

Simon

The one shuriken has fitted may already have the legs as did mine which have both come from dmgrs. They do make it more stable as the legs sit on the block. I compared the two as my original thermostat didn't have the supporting legs and noticed the difference in wobbly-ness

Hello, I've bought one of this.
Ivhope this will work, I drove yesterday but the car takes time to heat and the temperature remains at 80 degrees

Hello guys, I've fitted the new original MG Rover thermostat.
It no longer leaks, I lubricated the O-rings well when mounting and followed the Haynes coolant refil method.
My operating temperature is around 82° instead of 90.
What do you think? On the thermostat it is well indicated 82°, but on the forums we read that the ideal operating temperature of the kv6 is about 90°.
Do you have any idea what the problem is or is it normal?
Thank you..

Are you using the instrument pack diagnostics digital display Brahim?

Does it read 82° when the car is being driven? At what speed?

As the car is being driven does the temperature vary depending upon road speed? By how much?

I always recommend the MG Rover method of refilling and bleeding which I post a lot. The Haynes version contains an error. The expansion tank bleed hose should not be disconnected as stated in fig. 27.38. I hope you didn't do that.

Ignore the 82° marking moulded into the thermostat housing. The thermostat inside is rated at 88°, or it should be; mine is.

Simon

Hello Simon, i used the instrument pack diagnostics digital display .
Yes , the temperature vary depending upon road speed: between 90 khm and 130khm , the temperature is 82-83°.
In city, ,it's 84/100° depending the traffic.

I think I’m going to do a purge again because I disconnected the expansion tank bleed hose, I didn’t know it would be a problem.

Thanks for listening Simon .
Have a good evening.

Thanks Brahim. A sealed cooling system, pressurising correctly, should run in the low nineties whether the car is moving at 35 km/h (20 mph) or 130 km/h (75 mph). It should only rise to 100° when the car is stationary for long periods.

Your symptoms are a classic case of an unsealed cooling system. This could be due to anything from worn expansion tank cap seals, a faulty cap, a loose hose connection, a slowly seeping 'O' ring in the 'V', a defective water pump gasket or bearing, a leaking radiator, inlet manifold gasket etc. etc., the list is almost endless. It will not be easy to find because there won't necessarily be drops of coolant visible.
It won't be a problem provided that you reconnected that hose at the same time as lowering the expansion tank back into its fixed position.

Simon

Thanks you Simon, i'll check when i can.

I bought two thermostats, and the result is the same.
I don’t think they are defective, I have no leaks now but my temperature isn't as good as the other 75's owners .

I inspected everything again today without success. It takes time to heat and reach just over 82°( starting and driving 4 km in the city). I don’t think the thermostat is blocked.
Would anyone have a idea, please?
Thank you.

Hello mate!
Is your coolant temperature a concern?
Mine gives me in cruising mode between 75 & 85°, sometimes even 70°, controlled by Torque Pro. My engine works a treat and I'm not at all intrigued or anxious. Temperatures are lower when fuelling with full E85 (ethanol). Besides I've swapped for a slightly bigger radiator and have a slightly modified air intake giving more breath. If the engine is left in stand by for a few minutes the temperature is growing over 80/85° indeed.

Hello Dorcherster, excuse me I didn't have time to post on the French forum.
The temperature worries me because I rely on the indications given by our English friends.
I changed the thermostat when I fixed my fuel leak because the original thermostat began to leak.
I’m worried about damaging the engine or that the oil is not at the right temperature.
Thanks you

And not to forget the question of fuel economy. My V6 runs at a more or less constant 95 degs, confirmed by not only the onboard diagnostics but by Torque Pro.

Regards

I don't know where is the problem.
I will try to purge again because the last time, I only purged part of the coolant(5 liters).

95°C! Isn't it a tad high? Are you fuelling with full E85?
If so such a difference between yours and mine looks rather weird. :shrug:

Here is an example of a sequence a few days ago between 77 and 80° while cruising on an A-road (the 6,410 revs was a kick-down in sport mode!). Mind that the mpg (l/100 km) is overstated. In fact I'm doing a 22.6 mpg (12.5 l/100 km) average in the space of 4 years, but Torque Pro can't cope correctly with E85. The rather freezing temperature is a mocked one because of the 24k Ohms resistor which is tricking the ECU to give more fuel and comply with E85 stoechiometric ratio (1:14.7 instead of 1:9.7 for E5).


https://www.mg-rover.org/cdn-cgi/ima...04-png.136621/

I don’t think it uses e85 fuel but I will try to drive with E10 to see a difference or not.
Has your thermostat been replaced?

Not at all. All is 22 year old genuine Rover but the resistors.

Hi Brahim,

With your car's problems it is important that you carry out procedures fully. I recommend that you drain your cooling system completely, including the cylinder block drain plug at the left hand bank, and follow the MG Rover procedure exactly.

Dorchester2 has modified his engine so a comparison isn't valid.

There's no point in buying E10 fuel Brahim. It isn't going to make your engine run 10 degrees hotter.

Simon

Use standard 95 octane fuel which at the moment contains 5% ethanol. (E10 is being introduced during the summer with of course no views of the common motorist being heard).

We run four V6s here, three are used on a daily basis and all record roughly the same running temperature 92 - 95 degs, run with ACC active. I believe the standard thermostat opening temperature is 88 degs, so I'm quite happy with 92 - 95 especially as several others have confirmed the same sort of results.

Keep well

I'll try this Thanks you.

Good for you.
The reason why I thought you were fuelling with E85 is that you're living in Sweden. But I remember that the price is now less attractive.
Anyway why fearing E10? ... I can't understand. But that's another question and I don't want to begin an argument...
Keep you safe as well. Always glad to hear of you.

hello, I think I have a leak even though I have no trace under the car or in the v .
: o
I’m afraid it’s the water pump ( it was replaced 6 months ago but I had seen traces of dried coolant under the place where the water pump is mounted).
In fact, I smell coolant when I get out of the vehicle (hot engine).

Unfortunately, it’s not in my skills.
good evening.

i hope a new gasket was used. also there are i believe some of the mounting screws that are drilled straight through into the water jacket they will need to have sealant put on the threads. i hope it was a new pump fitted because they nearly always leek when they have been disturbed whilst fitting a new cambelt. when the belts are changed its recomended to renew all items. otherwise you could be back in there again with a leeking water pump 6 months later ... :shrug:

Clean off the traces of coolant residue Brahim and see if they recur in the same place. If the 'V' has seen coolant in the past it can escape through a gap between the water pump and right hand bank. This produces droplets on the oil filter and gives the mistaken impression of a leaking pump gasket.
Now it's just a matter of finding it! After stopping the hot engine, raise the car, remove the engine undertray and spend some time looking with a powerful torch.

I'm not sure what you mean Stefan. :confused: The KV6 water pump doesn't need to be disturbed.
The reason that people replace the pump is because to do so in future would involve repeating the cambelt renewal exercise. Unfortunately this can backfire as some aftermarket pumps have subsequently leaked. Possible reasons for this are poor quality parts and/or careless installation.

Simon

thankyou simon.i fully understand that the waterpump does not need to be disturbed or removed. what i was trying to suggest was that the release of belt pressure and re-applied was in itself a "disturbing " action on the bearings / seals within the pump itself. this may of course have been an assumption by other members rather than being a case of a pump that was ready for change anyway. if the belts were in need of change then the pump was about ready for change in any case. did the o.p say somewhere in the thread that the pump had been changed along with the belts recently ? if that indeed is in truth correct and the job has been done then as you say either poor quality parts or workmanship seems the likely culprit. ... regards stefan.....;)

Hello,yes it's a new water pump sir. But i don't known if sealant has been applied.

I agree that it is best to remove the intake to fit the new thermostat rather than use the "Keyhole" method That gives you the opportunity to change the intake/head gaskets. On one of my V6s one of these developed a leak that would drain the system in minutes. If one develops a small leak the thermostat could be blamed.
When fitting a new pump I found that some of the mounting holes on the pump had to be filed for proper alignment.
I also fitted Viton seals to the cap on the expansion tank to replace the original flattened seals.
There has been no comment on the Kaiser metal thermostat housing. Opinions?

Hello, where can i find Viton seals for the cap?
Thanks you.

https://www.ebay.co.uk/sch/i.html?_f...er+75&_sacat=0


https://www.ebay.fr/sch/i.html?_from...er+75&_sacat=0

That's who I bought mine from. Quality parts and a
very professional seller who I would definately recommend.

I had Kaiser metal thermostat fitted in April 2018 no sign of any problems, mind my mileage and speed are both low.😁

The Viton seals of my cap on the expansion tank are flattened . I will change these.

I doubt the ones on the cap are Viton, they should look like this below.

https://i.imgur.com/zRe2Bpdl.jpg1

There is one small o-ring and one large one.
https://i.imgur.com/fvoSdCLl.jpg2

https://i.imgur.com/jIfxtb4l.jpg3

https://i.imgur.com/RLSolxil.jpg4

At our Nano meets these are changed out FOC

https://i.imgur.com/xtgZZwfl.jpg5

Hello, I used mg rover filling method for coolant. No change. The engine takes a long time to heat and to reach just 80 82 ( it is very hot here in France).
I realized that the temperature oscillates: sometimes it displays 85 degrees then a second after 78 and then goes up . I had changed my sensor by a dmgrs, I did not keep my original bmw sensor.

When I disassembled my thermostat , some coolant has flowed on the sensor and its wiring. Do you think the sensor is defective?
The coolant level is stable.
Thanks you.

Have you done this yet Brahim?
You need to establish whether or not your water pump is leaking. You will see low temperature indications which vary with road speed if the cooling system is not sealed. Those are the symptoms you've reported (see post no. 16). You should not have changed the temperature sender without firm evidence that it was faulty and you should have kept the original.

Simon

Hi.
I'm still surprised that there are threads about this issue. I discussed this many times when I owned a KV6 a few years ago. I did my thermostat by the keyhole method. Its imperative to clean off the crud round the hole for the thermostat, it doesn't need to be shiny but there has to be a clean surface and bore with no pitting or corrosion and a nice grey surface. The Viton O rings must be properly lubricated with only Molycote 111, I keep banging on about this and will till the cows come home. Its not cheap but a tube will last for years. Do this once and then forget it. I also found some themostats are copies even those from reputable sources so beware, from memory it's quite easy to see inside and compare the difference between the original and the copy, all the ones that give cooler running are lower opening and not to Rover spec...... So beware.
The reason the temperature goes up and down is nothing at all to do with the odd drip when the engine cools its the poor quality themostats pulsing open and closing as their thermal range is less due to design.
So get your Molycote 111, new O rings and grease the rings so you'll not get leaks there any more unless the bore and facing of the hole is in a bad way.

PS use Molycote 111 on all your O rings in the cooling system, on the cap etc that is what it's designed for.

https://www.silmid.com/silicones/sil...ze-and-colour/

Hello, after having settled my tank problem, I now take care of the temperature of the engine because my fuel consumption is high.
The thermostat is new(original part changed twice) and no longer leaks.
I also changed the temperature sensor and the expansion cap.
According to your advice, it could be the water pump (replaced with the cam belts 8 months ago).
Do you think I need a new water pump? The level in the expansion tank is stable but the temperature remains stable at about 82° and rises to 100 in town.
Thank you

What is the problem? These cars do use petrol, so what is high?
What has the water pump got to do with it?
The temperatures are fine, it looks to me.

No!
That's too low and will cause increased fuel consumption. The only component that can be responsible for this is the thermostat. Your running temperature should be more like 92°. Either the thermostat is opening early or it's a version for hot climates or it's not a genuine MGR product.

Simon

I too have recently fitted a new thermostat and temp sensor supplied by DMGRS and am seeing the same lower running temps using the ipk on my KV6. Maximum temp when car is moving is 78 to 80° regardless of motorway or city driving and I the car will not get any hotter even if giving it 'the beans' Bottom rad hose starts to get warm around 75° and is too hot to hold at 78°. I contacted them with my concern that the car is running on the low side and they assured me that these kits come with 82° stats fitted not 88° as was fitted at factory. They said as long as the car sits in the 'normal' calibrated temperature range of 75 to 115° then not to worry. If the car struggles to maintain the minimum 75° during winter, they will replace the kit FOC. Who knows ??

Hello Simon, I bought an original mg rover thermostat kit (the one you recommended earlier in this forum) and another thermostat from DMGRS, but the operating temperatures are identical.
I had read that this could be from an unsealed system.
I would be surprised if I bought two defective thermostats. Perhaps they are no longer calibrated to open at 88°.

Good morning and thank you.
I am relying on the recommendations of the 75' owners .
I've read everywhere that the optimum temperature of kv6 is about 90 degrees.

I know that my fuel consumption will be better if the engine runs at the right temperature. I also noticed that it takes a little time to reach its temperature (82°).

Same as mine, as posted before and takes slightly longer to reach operating temperature than before with the new stat opening earlier.

Hi, it’s weird, maybe the new thermostats aren’t the same as the original ones anymore. Because most v6 owners have higher temperatures than ours.

DMGRS assures me that the batch is not known to be faulty and I trust what they say however, if not enough people (if anyone at all) report the low running temps to them then of course how can they be aware of any issues. 100% though they said these come fitted with 82° stats.

Unfortunately, I did not check what mine was running at before as I had the classic leak so just changed the lot. I'm assuming if it had an original MGR stat before, it would have been running hotter than it is now.

The things that bother me the most is come winter if the gauge struggles to reach mid way (75°), at the moment my aircon doesnt work so when this is working and the low speed rad fan is constantly running, will my car be EVEN slower than it is now to reach operating temp . Also how much running at 80° is going to affect fuel consumption compared to running at 90°

High fuel consumption is a well known fact of the V6. Worst with the auto box. These cars are not very fuel efficient, but driven with care can reach about 10km liter in automatic form.
I don't know where people have got this from, but only at very low temperatures and /or with a faulty temperature sender, will the fuel management system provide a rich mixture.
80 degrees is well above that.!
So to state the car has high fuel consumption (without specifying) and then suspect the water pump, makes no sense at all.
So I simply don't see any problem here!
Maybe just keep an eye on a possible water loss, and otherwise just enjoy the car.
Analysis paralysis is not going to help anyone!;)

This may help....

Message text posted by me on the 28th January 2017

If the drawings were passed over to the Chinese then replacements may well have been made to the newer specs.

That also makes much more sense!
here, driving the car on a summers day, stepping out of it, you are engulfed in a sauna, standing next to the car.
The temperatures are very high, and the engine bay temperature ridiculous.
I think my MGF is set to start the fan in the engine bay (not the radiator cooling fan) at 110 (or 105?) degrees from memory to keep the engine bay cool!. (it is a mid engined car)
So high engine bay temperatures are not desirable!

I consider myself happy, if any of my cars run at mid 80es!!

I would be happier with mid 80s rather than 78 to 80. I have noticed something when driving, not sure if it means anything...

(Aircon off as its not gassed, econ active)With atc set to coldest, driving around, the car reaches 75° on the ipk and then it's there for another couple of miles and seems to struggle with the climb up to 80° and during driving, temp slowly fluctuates between 78 and 80°

... atc set to hottest, engine temp will climb steady straight up to 80° and maintain this temp.

Now usually, it is the other way around whereby, when you use the heaters, it has a cooling effect on the engine and takes longer for engine/coolant to get up to operating temp?

When at full temp 80°, into neutral and coasting sees the temp rise to 81° and then back into gear and gas sees temp back to 80° under load.

I have the same thing on my car. I think the thermostat isn't as good as the original parts. The car takes a time to reach 80 82°.

thankyou for this usefull post phil. this backs up what i have always claimed about the performance of my kv6 during warm up and normal running since fitting my kaiser stat. mine runs around 82 degrees . good to hear. ..... ;)

1995? :eek: :confused: That doesn't make sense.

My engine has always run in the low nineties with the original factory-fitted (in 1999) thermostat, a Circoli replacement (in 2012) and the final part with the four supporting legs bought from an X-Part agent (in 2017).

Under test, my factory-fitted (in 1999) thermostat, stamped 82˚ on the housing (as Phil's quote states) actually opens according to the spec. in RAVE which is 88˚ ± 2˚.

It may well be that the opening temperature has been lowered, but this could not have been in 1995! I would like to see the engineering drawing from then to which X-Part refers.
Edit: Also, I've never seen a Technical Bulletin from MG Rover during the production of the 75/ZT concerning a change of thermostat specification.

To avoid low running temperatures (in the eighties) don't change your thermostat! Fit new genuine CDU 3858 'O' rings to the original (safely extracted with the LH inlet manifold removed) and set the straight pipe serrated clips fully outwards.

Simon

Didn't have a choice, the housing around the join was leaking. Did a 3 hour drive in the ZT to Goodwood today and on the motorway, the temperature settled at 78° sometimes reading 77° for a short blip now and again but always back to 78°. Didn't go any higher until the slower roads then crept up to 80° max.

i fitted one f the thermostats with the three pegs for stability that stat and the one before it all ran from 91 would reach 100 and the fan would kick in to bring it back down to 91.

I don't know what's going on with these stats but surely there must be some around with the 88c start opening ?

https://i.imgur.com/r5YEmWPl.jpg1

https://i.imgur.com/yFMdsfnl.jpg2

https://i.imgur.com/Ycf2KfYl.jpg3

https://i.imgur.com/tsgLR5Al.jpg4

It seems these stats have been talked about forever

https://www.the75andztclub.co.uk/for...thermostat+88c

Hello Tom,

Although it looks certain that this is the case, in fact it isn't! :eek: What happens is that the 'O' ring at the base of the housing flattens and a fine spray of coolant is then emitted upwards to coat the widest part of the housing; the seam. The solution is as I described in my previous post. :D

Simon

Don't forget the STO temp is when the wax stat STARTS to move it doesn't mean there is a lot of flow through it, they (x-part) say it is FULLY open at 96 but we know that around 89-90 there is sufficient flow to heat the hoses and radiator.

The other option to consider is the single temp sensor may not be reading correctly, i have seen one that got so cooked by over temp the ecu reading never went above 80C based on the sensors resistance reading although using external measurement showed the cooling system was much higher.

After the last thermostat change I did I have to agree with you, if the running temp is ok, nothing fractured then reuse what you have and fit new seals, we twice got faulty components from Rimmers, each time the curved pipe had a manufacturing flaw/damage which caused a leak (SIAC parts) the car was with us for over a week before it was sorted and leak free.


Try contacting x-part for a copy of the drawing.

Hi Phil,

How could I forget this after staring into many saucepans full of water with thermostats suspended! :D

The temperature when fully open didn't apparently change which also makes me doubt the accuracy of X-Part's reply to you.
Thank you very much for this Phil. I'm currently helping another member with his KV6 and the plastic curved pipe from an independent supplier well known on this forum, advertised as a genuine part, was too big to fit into the block, even with the 'O' ring removed! The supplier sent another one which was exactly the same. :rolleyes:
Ha ha! :D Did I hear someone say "corporate confidentiality"? :D

Thanks for your input Phil, much appreciated.

Simon

Have to disagree as when I removed it, you could see where the join had split.

My head is telling me to buy another stat to achieve a higher temp, my heart isn't really telling me to do the job again for the sake of an 8 to 10° gain!

Hi Tom,

Unfortunately a visual diagnosis alone is misleading. Had you filled it with water you'd have been surprised to find no evidence of a split. Nobody does this though, except for me! :D ;)

I fully understand your reluctance to do the job again, particularly when others are finding it difficult to obtain a proper 88˚ thermostat.

Simon

I'm following the thread since the beginning but I have a very silly question for you because I can't understand where lies the problem:
What's wrong with slightly low-ish temperatures say around 80°?
I thought the more dreadful problem was when temperatures were increasing too high...
Thank you to enlighten my knowledge. :bowdown:

Good question. I have been told different things by different people. Some have suggested around 80° the temp is not high enough for the oil to burn off the nasties and prevent sludging but oil temp are considerably higher than this anyway? Also some have said fuel consumption could be affected whilst others have said 80° hot enough for the car to not increase fuelling for cold running conditions.

The way I see it is although 80 is slightly lower than 'ideal' , it is within calibrated range of 75 to 115° , hot enough for the fuelling to be normal and the car seems to run perfectly fine. MPG wise, I am averaging mid 20s around town and 29 ish on a motorway run determined by brim to brim calculations, which appears to be normal for the KV6?

Well first of all the engine was designed to run hotter than that. This isn't peculiar to the KV6, or even MG Rover, petrol engines for the UK climate have always been like this since I started driving.

The oil temperature will be affected via the oil cooler or conduction. It will be lower viscosity and therefore will not perform as intended.

Fuel consumption could well be higher. I experienced this recently when my city car's thermostat started opening early. Only the ECM manufacturer and MGR will know the exact relationship between coolant temperature and fuelling so claims that 80˚ coolant won't affect fuelling is doubtful and speculative.

Possible reduced heater maximum output (diesel owners have complained about this).

• I'd say that 80˚ is more than "slightly" low Tom! :} It's 12 to 15˚ lower.
• The temperature gauge "normal" range has nothing to do with fuelling. It was programmed like that so that drivers wouldn't worry about normal variations in coolant temperature.

Simon

Can the inline thermostat mod made for the diesels be fitted to the petrol cars ?

HI Tom
No inline is only for the diesel cars.

That's a pig, means I'm going to have to do this thermostat change... Again....and then hope I don't have another low temp or faulty part.

Hi Tom,

To stand the best chance of getting a 88˚ thermostat I'd recommend that you buy only from an X-Part agent (such as E Car Parts 01767 682900, Summit Garage 01384 259555, A.E. Wilcox 01454 294213). Try your utmost to get one of the Chinese modified housings with the four supporting legs.

Simon

According to Torque monitoring, when cruising my KV6 engine is cooled on a relative large range of values from even 70/80° to 85/95° and always moving up or down even if slightly according situations.
As we all know it depends upon lots of factors: ambient temperature outside indeed, going uphill or downhill obviously, and motorways, country roads, towns or villages.
TBH I'm using the KV6 mainly on medium or long journeys (never less than 50km or 30 mls), and preferably outside towns & busy areas.
Never was I upset by low-ish temperatures say below 85°, rather reassured.
I don't want to see those temperatures flirting with the 3 digits.
Anyway in the huge French 1999 workshop documentation I've just received (10 kg!), as expected it reads that the thermostat initial aperture is done at 88 +/-2° and minimum at 96°. Fan speeds being: 1 at 100°, 2 at 106° & 3 at 112°, respectively stopping at 96°, 102° & 108°.
Besides to be kept out of trouble I'm always filling up every 2 or 3 year the coolant system with orange OAT fluid (MOTUL Inugel Optimal if available) protecting from -37° to +120° (I don't remember exactly the latter).
The engine is working a treat since 4 years.
At the last MOT (CT for us every 2 year) the pollution was absolutely nil, i.e. perfect & bang in the middle of the tiny range.
So no fuss to be done and no headache to be had...

Hello Simon, i've baught an original thermostat from E car parts ( on eBay), but the température is around 82° too.
:hausser les épaules:

Hi shuriken. Thanks for highlighting this. I was intending to buy my next thermostat from e car parts, if your reporting that these are also selling thermostats that operate at the incorrect temperature, then I won't be buying one from them.

Ill keep my thread up dated and reply here if I find a solution shuriken. :)

Maybe this has something to do with the Chinese versions? Wondering if the original part made in UK (but do not have the supporting lugs) will be the 88° and all Chinese variants are the lower temp.

Shuriken -

The one you bought from e car parts - did this have the little supporting lugs on the housing?

Thanks
Rob

Hello, sorry i don't remember this but i think no.

Okay no problem.

If you think they didn't have the little supporting legs, this may indicate that the original design is also prone to being fitted with the wrong thermostats inside. So an original design isn't a guarantee that it's going to open at the correct temperature..

I'll speak with summit garage tomorrow and see if they have any suggestions.

I imagine there will be other kv6 mg rover vehicles also running thermostats that are opening too early at this rate...

If you find the good Thermostat, tell us please.
Thanks you sir.

I'd also be very interested to hear what Summit say. My thermostat starts to open around 74° as the bottom hose is is warm from this temp. May explain why I'm only seeing 78° on motorway. Either my 82° stat is faulty or the housing I bought has a 78° summer stat fitted in error. Either way, I am not happy with how low its running given its in the warmer weather and not during winter. I have messaged DMGRS to see if they only have one supplier for these as I do not want to fit another one from them to have the same problem.

Hello, the thermostat I bought from DMGRS indicated about 82 degrees on the highway.
Clearly, these thermostats look all different.
I would like to find an original thermostat on a 75 V6 ( which has never been changed) and try to install it on mine.
But here in France, V6 are rare.

Unfortunately I didn't have time to ring summit today. I will be phoning them tomorrow.. them and x-part.

If you see my thread you will see I have been making a start of my cooling related issues and hopefully coming to a solution.

Matrix removed today and flushed thoroughly
Temperature control flap motors opened, checked and monitored (both sides) for operation. Both sides operating exactly the same and with no fault codes displaying on the ATC display screen.. all must be well their so.. there must be another issue somewhere.

In regards to the thermostats..I am going to do my best with getting to the bottom of the issue as I won't be paying out any more money in the hope "it works as intended" only to find another poor quality part.

I will be speaking with summit and x-part as I say and go on their recommendations for a thermostat and then will be testing it using a pan of hot water and a digital and an old fashioned thermometer for the belt and braces approach to ensure the thermostat opens at the correct temperature before even considering taking the upper and.lower inlet manifolds back off again..

Thing is.. the thermostats aren't cheap in comparison.. they also aren't the quickest things to fit either due to the design of the engine. I think it's only right that someone in that situation will be less than happy after completing all that work only to find the part isn't working as it should.

On a side note.. if anyone has any "official" documentation that backs up the correct operating temperature of the thermostat or cooling system then please post a screenshot or a picture. This will be massively appreciated.

Rob

Thanks Rob

Not a problem

Also to answer one of my earlier points.

I've just come across this in the rave manual.

[IMG]https://i.postimg.cc/t770yDsg/Screen...713-232455.png[/IMG]

Click the picture and it should open larger to show more detail. When the image opens in the new website, click the image again for best detail.


Using this link

https://www.the75andztclub.co.uk/for...=280437&page=2

Then clicking on the:

workshop manual - service procedures

Allow pdf to load

Go to page

97

Another update!
 

Another update.

Has been confirmed. Thermostat opening is 88°c. +/- 2°c meaning it can open from 86°c or open at 90°c.

The information posted in my last reply in regards to the rave information appears to be 100% correct. So...

I have ordered a new thermostat from summit garage and it will be arriving on Friday. It doesn't come with the required pipes or clips. Just the housing.

I will report back showing a side by side comparison of the current thermostat operating temperature and with the new thermostat.


A further update regarding my 75.
Having found uneven heat from the dash vents yesterday.. this morning I decided to pull both the hoses from the oil cooler and flushed the oil cooler and hoses that run into pipework underneath the radiator.

Bled back up correctly etc.. now I have heat that appears equal from all vents on both passenger and drivers side. Hurrah! (Hope it lasts now) haha.

However... Trying the air con again, rear passenger vents shut. Two centre dashboard vents fully open.

Drivers side icy cold.. passenger side, still blows Luke warm??

Put to the feet position.. exactly the same

Not sure what's going on there. Closing the driver's side vents completely and leaving only the passenger side centre vent open, it still wasn't icy cold as you would expect. No fault codes on the ATC and obvious issues with the temperature control flap motors
Anyone any suggestions?

Thanks
Rob

Kv6 Thermostats
 

Hello, I have just joined this forum - this is my first post - as I'm considering buying a 2.5l V6 75 Tourer which has a thermostat housing leak.

I'm considering fitting a "Kaiser" housing if I buy the car because I believe a metal housing is simply better than a plastic housing and pipes. But then I would want to change the thermostat itself to one that is suited to UK driving because I've read quite a bit on this forum about most thermostat opening temperatures being unsuited to cold country driving - including Kaiser's one. Does anyone know if one can successfully install a locally sourced thermostat that opens at the specified temperatures of 88-96 degrees, and also which thermostat and supplier is the one to go for?

Thanks

If you search for the forum member called Kaiser I believe he developed these thermostats and would be the best person to advise.

Best of luck and welcome to the forum :)

Hello biffa75 and thank you for your quick reply and your welcome message.

Reading through the thread again, and some others regarding the KV6 engines - trying to get my head around the many mysteries of the KV6 engine! - I see that you bought a "Summit Garage" thermostat which should open at the correct specified temperatures. I could be wrong here but I believe Kaiser only produces the housing and pipes in metal but uses a thermostat that seems to open at too cool a temp for UK cars. I'm aware that I'm new to the forum and that this subject seems to have been going round in circles for a while, so I don't want to tread on anybody's toes, but I'll contact Kaiser as you suggest to ask his opinion. But in the interim, have you managed to test the opening temperature of the thermostat your bought, biffa75?

I'm just wondering if I could just pop a "Summit" thermostat into a "Kaiser" metal housing whilst doing the work, and have the best of both worlds? I don't fancy spending three or four hours replacing a thermostat and housing only to find the thermostat isn't suited to our climate.
I imagine a South African spec car would have a cooler opening spec to prevent overheating in sustained hot weather, but I'm just guessing here.

If I can't arrive at a workable solution, I just won't buy the car. It seems silly that something like a thermostat specification is a mystery in these days.

I hope that this can be fixed once and for all, not just for me, but for other owners who have replaced, or who will replace thermostats, and found they don't/wont perform correctly.

It seems to be a very confusing subject involving several different thermostat suppliers/manufacturers? Thanks again for the advice.

Regards,

DMGRS KV6 "Kaiser" Thermostat
 

Hello again,

I've been doing a bit more searching around the forum and I followed a link to the DMGRS website. They sell the "Kaiser" housing and hoses etc. (currently out of stock till August) which is supplied with a Lucas thermostat already installed. However, they also supply a "Vernet 6773 Equivalent" thermostat which says 87C which I suppose is suited to the UK climate? DMGRS' phone lines are already closed but I'll contact them tomorrow, have a chat with them and report back.

Regards

Hello Aiden and :welcome: to the club.

If you buy this car the solution to the leak is simple and cheap. Keep the existing plastic thermostat housing so that your engine runs at the correct temperature. Next buy and fit four new *genuine 'O' rings (CDU 3858) and finish by pushing the serrated clips on the straight pipe fully outwards, then squeeze to tighten them. This last procedure is vital and the key to stopping the leakage.

* Buy parts only from an X-Part agent such as Rimmer Bros., Summit Garage and E Car Parts of Sandy.

Simon

Hello Simon and thank you for the welcome to the club, too.

Just to fill you in on the story, the garage that had the car when I saw it first isn't going to do any work on it for the seller as she doesn't want to spend anymore money on the car (she's clearing out her deceased husband's car collection). After I'd taken it for a test-drive up to operating temperature, there was water in the V despite the garage doing a "temporary fix" with K-seal or similar just so that it didn't overheat on her before she sold it. That's all she asked them to do for her.

I think, from what the garage said to me, the problem is not a failed O-ring but a cracked or split plastic housing itself. I'm not sure how replacing just the O-rings would solve the problem, unless I've misunderstood your advice. Would you mind elaborating a bit more on this for me please?

Regards,

Elaborating as requested!
 

Yes of course Aidan.

The garage will have observed coolant residue all over the central seam of the thermostat housing rather like that on my own car:

https://www.the75andztclub.co.uk/for...9e8ca7afcc.jpg

They can't be blamed for assuming that the housing had cracked or split around the seam but that isn't what's happened. I tested the housing you see in the picture off my car for leaks and there was none so I refitted it :eek: with new 'O' rings. There was no more coolant in the 'V' :D but the cure was only temporary. :o

After much investigation and trial and error on my own car I worked out the real reason. The 'O' rings were flattening over time, particularly the ring at the base of the thermostat housing. The resulting imperfect seal probably produced a fine spray of coolant upwards which hit the widest point of the housing, the seam, and created the familiar antifreeze deposits. But why were the 'O' rings flattening? More to the point, why were only some engines affected and why did the time taken for the flattening to occur vary from weeks to years? There have been various theories about this but the answer turned out to be very simple.

No-one had considered the purpose of the strange serrated plastic clips on the straight pipe. I noticed that another club member had suggested that the flattening of the 'O' rings might be caused by movement. A mild tug on the hoses attached to the housing confirmed his theory; it rocked quite alarmingly. This was the breakthrough. If normal engine vibration and torque reaction produced even minor movement, over time could this change the profile of the 'O' ring and cause a coolant leak? It was then that I realised what the serrated clips are for.

To fit the straight pipe/thermostat housing into the engine requires the pipe to slide longitudinally. Once everything's in place however, this is undesirable since the 'O' rings then cease to be just a seal but become a friction joint or a basic bearing if you like. If the two serrated clips are pushed in their channels firmly against the water pump and thermostat housings, the assembly becomes rigid and movement is impossible. With this technique my engine has been free of leaks for over four years now (and it runs at the correct temperature in the low nineties).

Further evidence confirming my findings is that the Chinese have improved the thermostat housing by including four supporting legs at the base. They must also have realised that movement, or to be more specific "rocking", of the housing was the issue. I have one of these fitted to my car and if you can find one, they are the best choice.

I'm sending you a PM as well Aiden.

All the best,

Simon

Simon, great write up and you are 100% correct on the serrated clips providing rigidity to the assembly
Many thanks for this tip that you gave me some months ago!

In regards to the thermostat housing with the four supporting legs... My latest thermostat from summit garage in Dudley that came from x-part that had the saic roewe and mg branding, didn't have these four legs. Being fitted to the car, it didn't appear any less stable than the previous faulty thermostat that had the four legs.

If anything the elbow pipe was less stable than the housing and straight pipe assembly once all fitted nice and snug.

I aren't sure who is actually making the thermostats with the four supporting legs, but my from my latest experience, they aren't made by saic. Do you know who manufactures them? Would be good to get a name.

Rob

Thanks for this Rob. I agree with you that correct setting of the serrated clips is the most effective procedure. The four legged versions of the thermostat housing just add a bit of extra stability.
I don't. Mine came from E Car Parts four years ago.

Simon

Hello and welcome Aiden, when you get the car, the first thing to do is flush the system a few times to remove as much of the Kseal as possible, this stuff causes blockages in your heater matrix (normally blows cooler on the passenger side when it’s blocked)

Secondly, remove all the thermostat components and inspect them for cracking, age and OAT coolant does no favours to the material that the thermostat housing and particularly the elbow pipe are made from.

Good luck with the car, a days work should see you sort the issue.

I went through this when i had my MGZT 190, Simon kindly sent me some O-rings which i fitted to the housing with the stabilising lugs.

I think at the time i was the first to fit this type of housing or one of the first few ? it was still on the car when i let it go in 2018

https://www.the75andztclub.co.uk/for...d.php?t=177152

Hi Andy,

I'm afraid that age and OAT antifreeze were the clutches at straws which motivated me to find out the real reason.

My straight pipe is the original, now 22 years old. My curved pipe is 12 years old and I've never had leaks from either of them so the age theory doesn't hold water!

OAT isn't the issue either otherwise my straight pipe would have failed after 22 years exposure to it! :D Many more members also use 50% OAT and have never had leakage.

Simon

General Thanks
 

Dear All Members,

Thank you very much for all the welcomes and advice. It's a very helpful and welcoming forum.

I think that for cost reasons, I cannot justify stumping up for a metal thermostat - even if for future peace of mind - if it's just the O-rings which have failed. The cost of metal parts plus the breathtaking year's road-tax for a 2.5 V6 are worth more than double what the seller has been offered by a certain indiscriminate car-buying website, upon whose price I shall nevertheless base my offer to the seller, should I proceed.

To summarize all the advice I've received:
1) If thermostat housing/pipes have not actually failed, suspect/inspect and replace O-rings, and pay close attention to the serrated clips when reassembling.
2) If at all possible, try to get the "four lug" plastic thermostat housing as a replacement if a new housing is indeed required. (Trying to identify and actually buy a suitable thermostat itself seems to be another kettle of worms, but I'm assuming the "four lug" thermostat housing sold in the UK has the correct thermostat inside?)
3) Thoroughly clean the thermostat housing and engine/water pump areas where the thermostat and pipes interface/connect.
4) Flush engine of all coolant several times & check for a balanced performance of interior blower motors; driver vs. passenger side.
5) Keep and eye on coolant levels FOR EVER whilst owning a Rover 75...

Right now I'm also mulling over the "death rattle" that I heard emanating from the top/rear of the engine whilst idling at operating temperature. I've read the buying guides and troubleshooting info on this forum about the possible V6 issues and this car seems to have at least two; the death rattle and leaky coolant in the V... plus a very droopy headlining (Tourer version), door mirrors that don't fully adjust, and the car sounds quite noisy inside whilst on the move which suggests an exhaust leak or a loose metal brace above the headlining. The car has done about 134 000 miles and is being sold by the original owner's wife.

I still haven't made up my mind about buying this car, but even if I decide not to, I hope that this thread serves to clarify the thermostat issue a bit more for other people.

Regards,

Even though I’ve been on this forum for a good while, I share your confusion about these new thermostats and I don’t think we’ve got a definitive answer yet. Not so long ago the rear upper arms were a similar subject of discussion, I believe that question has been finally resolved by DMGRS listening and then commissioning their own branded upper arms. If I needed a set, there’s no way I would take a chance on ebay, or even Xpart ones as there’s no guarantee that they’re up to spec. I wouldn’t be surprised to hear news of branded DMGRS thermostats in the near future, or as soon as they can assure us of a proper 88 deg thermostat.

At the moment I wouldn’t buy a new thermostat anywhere (including DMGRS) and would rather re-use an old one I’ve got up in the attic.

There have been several promises of solutions to the death rattle upper manifold through the years, all have fallen flat. I’m currently examining a new Chinese KV6 manifold I’ve got on the workbench.

Regards

PS I'd suggest adding "replace inlet manifold gaskets" to your list, very easy while doing the thermostat and cost little.

I'm hoping to finish putting my 75 back together tomorrow with the new thermostat supplied my summit garage.

Although it doesn't have the four lugs, if it opens at the correct temperature, would this not be preferred over a thermostat without the added supporting legs seeing how it is the original design?

If the thermostat does open at the correct temperature, I would in my honest opinion, purchase the thermostat housing from summit garage in dudley Simply because it works I aren't sure of any other parts suppliers that may have a correctly operating thermostat. E car parts and dmgrs thermostats people are having issues with them opening too early.

Shame we don't know who the manufacturer is of the four supporting legged type thermostat

Totally agree, don't care if it has legs or not as long as it opens at 88 degs I'd be happy. What troubles me is that even though I value your recommendation of Summit Garage, we have no real idea of how many they have, what happens when they run out? How do we identify 88 deg thermostats compared to 82 deg ones? With the low temperatures we get in Sweden an 82 deg thermostat is relatively useless without even considering the time/work involved.

Regards

If the thermostat I have fitted (supplied) by summit garage works correctly and opens at 88°c, then they are to my knowledge and personal experience at that point a source of good kv6 thermostats. ( I will find out tomorrow all being well if the thermostat works correctly).

I was told by summit that they order directly from x-part. When the part arrived, it came with the saic roewe and mg branding stickers on the outer packaging indicating that it is authorised as a genuine or as near as genuine as possible and should meet the required quality standards set by mg rover. The best thing I could.suggest at this current stage if the thermostat I have actually works correctly, would be to speak to summit garage about any concerns you have.

I have been told x-part are currently looking into the current issues at manufacturer level in regards to the thermostats opening too early.

If there stock runs out, I'm sure they could order a batch or however many from x-part. X-part approach manufacturers with all the technical information and then carry quality control over the product to make sure it works as designed and intended.

So if they do run out it shouldn't be an issue. (As said they are currently looking into an issue possibly at manufacturer level).

Other than actually cracking the new thermostat open when it arrives (rendering the unit useless afterwards) and testing the thermostat that way with hot water etc, there's no real way of knowing for absolute certain until it's fitted into the car.

I have tried using hot water and pouring it into the thermostat with 3 of the four ports blocked off and watching for the springs inside moving indicating movement but it isn't easy.

Just like they did with the genuine upper arms? Thanks but I'll pass and use re-use my old one should I need it.

Regards

Best of luck :) I went to change my o ring on my original stat.. unfortunately the base of the stat broke where.it goes into the block.. so had no choice.

Im doing what I can to hopefully get something done about the thermostat issues as I won't be buying a Kaiser kit (as good as it may be).. it's an expensive upgrade I won't be forced into buying.. the orginal plastic design should be sorted.

In regards to the Indian upper arms.. I did so some reading about them.

Who was selling the arms? Did x-part actually confirm they were selling the arms to parts specialists?

Regards

X part had hundreds of the Indian arms in stock at the time they were found to be defective.

Some helpful tips, hopefully!
 

Accidents can happen the first time this job is attempted. Use lubricant on the 'O' rings and keep the housing near vertical throughout. Always bear in mind that you're dealing with plastic so controlled, limited force is the answer. :}
How about heating the whole assembly in water then, when it reaches say 85˚ but below 88˚, whip it out and quickly pour water into the lower radiator hose port to test for opening.
Aidan, I think you can do better than this tourer. It has a lot of problems, not least the K-seal which is extremely difficult, if not impossible, to remove. It causes havoc with the cooling system, other members being driven to despair by unpredictable overheating and coolant ejection. The "death rattle" indicates that it needs a replacement manifold chamber which means waiting for one to be offered second-hand unless you can stomach the high price of a new one. The drooping headlining is an unusual fault and it all adds up to a car which perhaps hasn't received the care and attention it deserves.

Simon

Andy i think quite a few others seller did and do still, ECP Rimmer bros, they are most likely still trying to pass them on to us, therefore anyone purchasing new rear arms i would ask what make they are and from when as i presume it is only DMGRS that as the latest new arms which are stamped with DMGRS on them.

https://www.dmgrs.co.uk/collections/...37476407836835

Thanks for the info Simon. I couldn't say if I had been a tad rough when removing the original unit, what I do remember is it being -5°c I suspect it was the original 18 year old thermostat and with those temps I put it down to age.. I do lubricate o rings upon assembly as I have done for years on other cars I've owned.

As for the Indian arms issue, if these were being sold via xpart.to.other parts outlets.such as Rimmer's etc.. that really isn't good, even more so if the arms are still available for sale! Surely xpart could look into the concerns of quality. After all, a thermostat.opening too early is one thing.. a major suspension compenent failure could prove fatal not only for passengers but also other bystanders..

Quite right, loads of sellers including DMGRS! https://www.ebay.co.uk/itm/293506246...AAAOSwi-BeZ77W

Scary,

Back to the subject of thermostats..

Finally got the car back up and running, bled the cooling system and then allowed it to cool and checked the level (was still over the max mark inside the tank). During driving at lower speeds i.e 30mph the engine temp.hovered around the 86-88°c area and sometimes slightly higher.. when climbing hills the temp ran higher at around 84-86°c.

At motorway speeds the temp was.coming back at 84-87°c.

Appears cyclical, which leads me to the think I still have an air lock (with the coolant level above the max tab inside the tank too...)

I'm going to allow it to cool, remove some of the coolant in the tank and take it to the max tab inside and wait for things to stabilize and report back

With the increased temperature readings despite being a little all over the place.. if the above doesn't improve the situation, it could be a faulty temp switch but I'll put that as a last resort.

The fact that it's running hotter than it ever has with the old thermostat.

Rob

Thanks for the update but it seems that your faith in your supplier might be misplaced. It might be running hotter than it ever has but has a long way to go before matching my near constant 95 deg which I consider to be normal operating temperature.

No new thermostats for me, I'm starting to think that Stocktake's idea of a remote diesel type solution might not be so daft, but perhaps with a 1.8T style dummy thermostat in place of the standard one. At least then we could easily swop a thermostat should it prove unreliable.

Regards

No problem,

If it does turn out to be a faulty thermostat again... I'm sorry to say but my time mg rover will be coming to an end. With issues over rear arms, duff thermostats despite best attempts and the money involved for potentially NAUGHTY WORD-NAUGHTY WORD-NAUGHTY WORD-NAUGHTY WORD- parts as a young family also trying to save a deposit to buy our first house.. I can't continue this way.

Using a remote thermostat may be a solution and should work however.. if the original thermostat cracks or thermostat jams shut, it would.still need replacing and the point of paying the money for what you know is a poor part.. isn't something I'm prepared to put up with unfortunately


I'm going to give it a little longer and double.check other things and make sure the system is free of air. I'm hoping this will stop the temperature fluctuating.

Thanks
Rob

Even though not ideal, an 82 thermostat should work in most conditions in the UK climate, sometimes in the dead of winter you might miss those extra degrees, I’d miss them a lot more.

My advice would be put up with what you’ve got but contact the supplier with your findings, hopefully you might get a refund.

The 1.8T has, I believe, a dummy thermostat, the bare frame but nothing internal so it’s open all the time, hopefully it will all be solved long before such a step is needed, but it’s a Plan B.

Regards

Hello biffa, I understand your disappointment, I am in the same situation.
I’m gonna stop bothering with the thermostat right now, I need toi fixe my auto gearbox .

I bought two thermostats and the result is always the same. My running temperature is about 82 degrees, and it takes time to heat the vehicle.

I would change the thermostat when I found a reliable supplier. Unfortunately, I live in France and I don’t know the English dealers.
Also, import taxes have gone up.

Goodbye.

Thanks shuriken, my previous thermostat sat at 82°c regardless unless stuck.in traffic.

The new one sits higher but it fluctuates.from.84-96°c. I'm just going to ignore it and keep and eye on the level. Make sure there's no air locks and.be done with it.

Regards

That is the one Kaiser told me to get, works fine. Can't remember where I got it, but found on internet.
Terry

Of course it fluctuates! What on earth are you expecting?
This is perfectly normal!
Why don't you just enjoy your car and stop worrying?
The time to worry is when it overheats!:D

Thanks for your reply kaiser :D

With it fluctuating, I would have thought it would hit the operating temp of around 88°c and at least stay there at the very least or go a few degrees above, not fall back to 84°c surely at 84°c (motorway speeds) it would either partially shut or fully causing a flow restriction wouldn't it?

There are a lot of factors to work in. If you are using the heater, you have that as an extra radiator. In cold weather that can almost cool the engine by itself.
As the water runs through the heater at all times, this is not something the thermostat can adjust for! You might also have a jiggle valve, a small hole or even a rubber flap in the thermostat. That also will allow water to pass uncontrolled. The thermostat itself will only start to open at the set opening temperature, and gradually open more and more, until it reaches fully open, about 10 to 15 degrees later.
The load on the engine varies, the ram cooling effect varies and the water temperature can therefor never be constant.
And what temperature is right?
The reason for later years higher running temperatures has a lot to do with modern technologies. There is less space in the engine bays, there are smaller radiators, less excess capacity, higher specific output and a tendency to run higher temperature for two main reasons. One: emissions and Two: better evaporation of water inside the engine.
But to claim that fuel economy is affected by running the car at 85 rather than say 95 is just idle talk. There are no fuel adjustment made at any temperatures above 60 degrees on any system I have ever heard of or seen. I guess maybe down to about 55 degrees.
So be happy your car does not overheat, and don't let some 5 or 8 degrees spoil your life. It is for all intends and purposes a safety factor and beneficial!!
I could think of many many other things in life much worse than that!:D

And for anyone to claim otherwise, just ask them to prove it. Simple as that. Relax, enjoy and watch out for high temperatures!

Hi Kaiser

Thanks for your reply, if this is the stance on current kv6 thermostats (that they may run a little cooler) for whatever reason could this information not be made a sticky or something on this forum for people to read through. As stated in the rave manual and by xpart. The thermostat minimum opening temp is 86°c. As myself and others have found.. new thermostats clearly aren't operating at this temp so.. here lies the confusion (perhaps by parts being updated or simply out of date information).

If the ECU isn't over fueling the engine, due to the lower coolant temps being recorded then I don't have an issue at all..
But who would have this information as I'm sure sure Siemens won't release this info..

Anyway.. the new stat doesn't leak, the level appears stable, I have even heat flow from the dash vents..



Regards

So, there you go. No problem.:D
If you want to know the operating temperature on the thermostat, you can open a discarded unit and see if/what is etched or printed/stamped on the unit.
I have a 80 degree unit in mine. Today we have a cold day here, 13 degrees. I made sure the car was filled with coolant, and off I went. Leisurely driving. Heater off. Temperature on dash showed 80 degrees rather quickly, within 2 km I guess. And then it sat fairly constant at 84 degrees for maybe anther 5 km. After that it started to rise to about 95 and go up and down with stops starts and speed.
So to me it looks as if when the first batch of cold water in the radiator is being used, things are pretty stable, and you will see temperatures of maybe 5 degrees above opening, until the water in the radiator has been through the engine. Then the flat spot moves up another 5 to 10 degrees.

I think the Chinese have started fitting 80 odd degree thermostats in their units as well. And to me, that makes a lot of sense.

And I promise you, that will never make the fuel mixture rich!

So I hope you now feel much better!!:D

We did ask someone 'in the know' some time ago (the name escapes me, but if it comes back to me I'll report back) at what temperature the ECU will start to adjust fuelling.
The answer was quite complicated but ultimately above 75 degrees (mid-way on the temperature gauge) the ECU will be fuelling 'normally' and not adjusting for the running temperature. I think the actual temperature for the cut-off was a few degrees lower, but I can't remember the exact number.

No 75 for me this time around.
 

As much as I'd love a Rover 75, it seems to me that there are just too many issues for someone in my situation to deal with.

I am searching for a reliable and relatively simple second car and, although I can do a lot of work on cars myself, I'm not in a situation to deal with a car that seems to have such complex problems such as over-heating and inlet manifold faults.

I wish I was in a more fortunate situation where I was able to own a Rover 75 as I've wanted one since they were released but, such is life.

Happy motoring to all you 75 owners. I hope you are all able to use your collective knowledge to resolve the issues of these desirable cars. Maybe oneday, to quote a famous Austrian...aahll be buck.

Regards
Aidan

These results indicate that your cooling system isn't perfectly sealed. Have you checked the expansion tank cap 'O' rings? They flatten over time.

:wot:
You're spot-on here Rob.
I'm afraid you're mistaken there Kaiser. Recently the fuel consumption of my urban car increased by about 3 mpg and, at the same time, I noticed that the engine was slow to warm-up and was barely reaching normal running temperature. I tested the thermostat on the bench and it was opening early, at around 82˚ (the spec. is 89˚). When replaced, the fuel consumption and coolant temperature returned to normal.

Simon

You are always able to talk, Simon. Now let's see some proof! Show me a system that will adjust air/petrol mixture for engine temperature above 60 degrees!

Hi Aidan.
Go for a diesel then no over heating problem then,;) upgrade it for more power, win win situation.

Easy to service, some later ones do not have the UBFP some have the FBH so you are nice and toasty in the winter, i know of a nice one coming on the market in near future due to the owner not being able to drive it anymore, well looked after one fail in 2009 on a Nearside Rear coil spring fractured.

:laughing2: It isn't "talk" Kaiser, it's real life evidence which unfortunately contradicts your belief.
You show me one which won't! The truth is Kaiser that neither you nor I knows how an engine ECU is programmed. The manufacturer will guard that information with the utmost security. You believe that an 80˚ coolant temperature won't result in higher fuel consumption. I know that it does because I took the measurements over real driving conditions and made sure that nothing else changed.

I am very happy for you to hold a contrary view Kaiser. Shall we move on?

Simon

Has anyone successfully changed the thermostat kit using the keyhole method mentioned on the forums (removing clips, refitting them nice and tight with access etc etc). Don't fancy removing manifolds again when I fit my replacement.

Kaiser
Great post I used to work for mg rover and spent a lot of time at the proving ground testing these cars before the launch and checking running temperatures etc you do have good information on these cars :D

Yes done loads via the keyhole method think I was one of the first people who said it can be done and I'm sure others on here will also say they have seen me do it

If you don't fancy doing it yourself bring it here and I will do it for you

Dave

Yes but the photos are now missing :mad:

https://www.the75andztclub.co.uk/for...=177152&page=4

My last post will be on this thread I think..

The point I was making here alongside trying to help others despite the thoughts and beliefs of others is..

If parts sellers are advertising a product, you buy said parts or products expecting that part or product to work the same way as the originally designed item "unless" otherwise stated.

My gripe.. how many times has the "mgr were penny pinching before Longbridge closed" comment been made on this forum.. if mgr were going to the extent of removing the plastic seatbelt anchor bolt plastic covers.. not to mention rear anti roll bars etc.. then why didn't mg rover fit 82°c thermostats to accommodate a wider range of ambient temperatures for hotter climates? Must have been a reason! Seeing how when my other thermostat was "only" just reaching 82°c on my 7 mile drive home in -5°c temps and by only just I mean a couple of streets from home..

Do a Google search, the normal running temperature for most modern engines is between 90°c or more the designed thermostat opening temp for the kv6 is 88+/-2°c so why the change to a lower temp?

Kaiser - I appreciate your offers of reassurance and I am now taking the approach of "why worry". As said above.. - as you stated though Kaiser after 5km's your temperature reaches 95°c
. The newer thermostats don't! I can drive as I have done recently at 70mph for over 200 miles and still be sat at 82°c the entire time. With the heater off with outside temps above 20°c.

If the thermostats that are available today, do run at the lower temperature.. advertise it to the buying public and inform them of the change in running temp to prevent confusion amongst owners. Had I been informed when buying, that the running temp was lower, but also been given a brief offer of reassurance that it is not an issue
. I couldn't care less. Why should customers/owners purchase a part and then be worried that there's a potential issue and have to go through hoops to find it may not cause any problems.

As said above.. most vehicles run a minimum of 90°c.

My thoughts.. saic are making the parts (possibly in China) a hotter climate where the car effectively continued until 2016 where the climate is hotter. The 88°c stat wasn't working well so.. 82°c stat was used and this is all that is available for all kv6 engines now for cost savings..due to the decline in parts demand due to numbers falling away...
just my personal thoughts..

With regards to another thread offered by stocktake in regards to modifying the top hose and fitting an inline thermostat. (This is by no means a dig or anything negative aimed at anybody). I personally don't see this as a fix.. more a bodge because the originally designed part isn't made to the required specification. It isn't something I would be looking towards doing. (Can't we just have a thermostat that works as originally designed?)

If this was any other car current or not and a replacement thermostat was found to be opening earlier, resulting in lower running coolant temperature.. I'm sure the part would be returned as defective? Wouldn't it?

Apologies in advance if this causes anybody any Ill feeling. This isn't particularly an issue to cause I'll feeling.. it's just a thermostat when all is said and done. I appreciate others views and comments and take these on board.
I would like to stay on friendly terms with the people of this forum/club so I won't be commenting on the kv6 thermostats any further for fear of causing upset or ill feeling.

R

it makes one wonder if these 82 stats have been reprogrammed into the chinese ecu set up. as simon rightly says we do not know how these are mapped for sure at which and what temperatures cold fueling ceases. one question that has not been asked is what temperatures does closed loop come in ? once in closed loop then fueling is under the control of o2 sensors and will fuel adaptations accordingly within i believe + 20 or - 20 . once outside of these values the trims will not operate within boundries and hence will throw an engine malfunction light. this i dont think is happening so must be in spec. unless people are not reporting this. ...:shrug:

According to my Technical Brochure (which is called a Kompendium here) the cut off temperature for the coolant sensor is 18 degs C, after which Lambda 1 takes over.

Some might question the fuss about 82 thermostats but not all of us live in temperate zones, minus 20 even 30 is not unknown here and votes for a 82 thermostat would be few.

I just want our suppliers to be honest: are their thermostats original spec or not? And ideally the temperature should be stamped or clearly visible on the item supplied.
Very few on here would knowing buy the Indian upper arms although they were supplied by Xpart and presumably approved - I feel Xpart are being dishonest passing off these thermostats as original spec ones. They are not.

Regards

of course they are !! the wording is ambiguous in as much as "original spec "means or implies from saiac motors. xpart will supply what they can get thats all. you will see time and again original rover in aftermarket parts meaning the chinese manufactured parts. so its obvious they cannot be original. if you read back to a recent post on here by phil-t4 around the 7th of this month he has posted a reply from xpart about the stat opening values. they have been altered a long time ago before the chinese did their version. however from the blueprint he recd by email it does not say what temps they were altered to ! so all in all yes it is unfair to mislead people as to what you are actually buying. i agree entirely.

That indicates a thermostat that does not open correctly and this is could be the equilibrium temperature once hot. IOW little or no thermostat regulation.

Maybe you would care to explain?

I have had maybe 5 or 6 stats fail on me in my life. Most have failed stuck closed. Other have been stuck partially open and unable to regulate. I have never had one that suddenly opens 6 degrees below spec, and otherwise functions correctly. I therefore cannot put much faith in your "test" and obviously none in your conclusions. That thermostat was faulty. Full stop.
I have run with my thermostat for more than ten years and not incurred any fuel penalties.

Yeah, we can move on, when you bring some meat to the party, and stop just quoting chapter and verse!
When I need scriptures quoted I go and nod off in church!;)
So let me do the work for you! Again!

http://archive.retro.co.za/archive/c...h-Motronic.pdf
Bosch, Combined Ignition and Fuel-injection system Motronic, Technical instruction. P22 Adjusting to Operating Conditions: Cold Starting, graph Duration of cold start valve operation as a function of coolant temperature, switch off 55 degrees Centigrade. P24 ill. 51 aux air at idle vs. engine temperature, cut off at 80 degrees P26 illustration 54 Enrichment as function of temperature, cut off at 80 degrees.

https://www.calameo.com/books/002414077b9b2f09ad1c6
Page 50: Even in the coldest weather the engine will have warmed up sufficiently for the mixture to be dialled back to near nominal values within 2 to 3 minutes.

Since it is difficult, if not (so far) impossible to obtain the exact values for the Siemens ECU used in our cars, we have to use our thinking caps, and find pointers elsewhere. Here is a bit of the MG control system, where temperatures are mentioned for oil, used as a substitute if coolant fails. The oil temperature in the MG is normally substantially hotter than the coolant, in a warm engine, and increasing with load.

https://www.mgfcar.de/library/ENGINE...VVC_MEMS_3.htm
Engine Oil Temperature Sensor
The engine oil temperature sensor is located in the oil filter housing on MPi engines and in the Hydraulic Control Unit (HCU) on VVC engines. The sensor provides a signal which allows the ECM to adjust fuelling values according to engine oil temperature, to produce optimum engine performance and minimum emissions during the engine warm up phase. On VVC engines, the ECM also uses the oil temperature to derive the viscosity of the oil passing through the HCU, which indicates how quickly the VVC mechanism will respond. The engine oil temperature sensor consists of an encapsulated Negative Temperature Coefficient (NTC) thermistor which is in contact with the engine oil. The engine oil temperature sensor operates in a similar manner to the ECT sensor. If the engine oil temperature sensor fails, the ECM will substitute a default value which is ramped up 80°C (176°F). This condition will not be apparent to the driver, with the exception of the temperature gauge which will display incorrect readings depending on the sensor failure.
The vehicle will run but may suffer from reduced engine performance and increased emissions as adaptive fuelling is disabled. The ECM will store fault codes which can be retrieved using TestBook.

If you go for programmable aftermarket EFI's, then there are instructions on how to set the values, also the value wehre the engine has warmed up. As for example here:http://www.fc-design.jp/en/FiEcuManu...sh_release.pdf
Read it yourself, for a change, but in there, you will find that the setting for engine warm up on mixture usually will be reduced zero once the engine is warm around 70 to 80 degrees.

Well I have a special link just for you!!:D A whole catalogue with different stats and opening temperatures!
http://www.t-a-s.co.za/thermostats-c...ue-TAS2018.pdf
Here you will see 1: that many cars do not run with hot stats, many do. And what is more 2: there are different stats for the V6 in the Rover and in the Landrover, and by Golly!! there is for the 1.8 Rover, MG and the Landrover with the exact same engine! So a Landrover can run a 1.8 with a
75 degree thermostat 5275B and Rover/MG can run the exact same engine with an 88 degree thermostat 5288B.
That, if nothing else, should even be able to convince our plastic guru that nothing in this world can be trusted!! How can Rover know what they are doing?
Well, he has a point, if they knew what they were doing at all times, maybe they would still build cars?? That is just me! But Rover for all intends and purposes is an ex producer, they have passed on! if they were not nailed to the perch they would have fallen off!!:D
You choose a stat for the hot climate, not the cold. China in areas is so cold you would not imagine! But I will leave that to you to discover.
And for finishing, just a response to our Swedish cold contributer:
18 degrees? :shrug:
It seems to me you have not fully grasped how a thermostat works and what it can and cannot do. In cold climates, thermostats are not fully able to control the engine temperature, because the heat losses from the exhaust, and the heater, and the engine to surrounding air is so large that the water in the radiator in many cases do not even reach the start point of thermostat opening! In that case, please explain what an even higher opening temperature would do for you! Absolutely nothing.
As you undoubtedly know, one solution in these cases is to fit a mechanical barrier to cold air entering the engine bay.
And to pour cold water on the wound, look at the thermostats for VOLVO. I am sure you know VOLVO is Swedish, and they should know something about cold weather, nes pas?
Some VOLVOs were issued with thermostats opening at 74 degrees! I guess these cars also came with a warning not to be used in cold weather of the coldest parts of Sweden! :getmecoat:

But seriously. I haven't got time for all these games of Simon says! It is a drain on my time. You should now have enough reading material here to keep you busy, who knows, maybe even create informed consent!
I can only urge you to think, enjoy your cars and be happy if you have a thermostat that opens.! Whether that is at 82 degrees or 88 degrees. If this difference can ruin your enjoyment, cost you money and make you loses sleep then you have too little to do!:cool:
Standing with an overheated lump waiting for the AA is not my idea of fun!
__________________

You doubt the 18 deg figure? Well I know you are familiar with Danish and perhaps Swedish is close enough: “När motortemperaturen har kommit upp till ca +18 grader C krävs inte längre någon extra uppfetning och bränsle/luftblandningen styrs då med Lambda 1 som riktvärde” source Rover 75 Tekniskt kompendium.

“I’m sure you know Volvo is Swedish” really? so Volvo (cars) is Swedish again, how nice, thought the Chinese had ownership.
A quick check on thermostats reveals this:
Thermostat, Coolant 92 °C
Volvo 850, 900, C70 (-2005), S40 V40 (-2004), S60 (-2009), S70 V70 (-2000), S80 (-2006), S90 V90 (-1998), V70 P26, V70 XC (-2000), XC70 (2001-2007)

And I know you are familiar with SD1s too - so am I, my wife & I used SD1s for many years summer & winter. 82 deg thermostat in summer but 92 in winter with further measures like cardboard in front of the radiator and even removing the viscous coupling complete with fan blades. Without these winter measures the car resembled an igloo with frost on the inside. And I was by no means alone: many owners swopped thermostats summer/winter back in the days when such a thing was still possible, even those who owned Volvos.

So please enjoy your own 82 deg thermostat and I will continue to enjoy my 88 deg one.

So you take that for true, not a chance of a misprint you think? Be that as it may, it just strengthens the argument that temperature ceases to be the main driver of mixture ratio well before the engine temperatures we see.
Again, Vitesse, please explain how a 92 degree thermostat will make your car hotter, if the cooling prevents the water in the radiator from reaching the lower trigger point for the thermostat. All you other antics point exactly to my point, prevent excess cooling by blocking off flow of cool air. That result could be exactly the same with a lower opening temperature, until you can exceed 82 degrees.
That other people did/do the same does not mean anything, except exactly that. The madness of crowds. Very apt for the times we live in.

As for VOLVO, I just pointed out that some of these cars, designed for Swedish conditions also were issued with thermostats opening at 74 degrees. That were in the days when these cars were fully Swedish with a good deal of British Imperial thrown in for good measure. And yes they are Swedish, and among the most popular cars ever sold in Sweden. They have not got a reputation for shoddy workmanship, and weak heaters, if anything, quite the contrary.
That is the point really.
So, enjoy your thermostat, just don't fret unnecessarily!:}

"kaiser- That indicates a thermostat that does not open correctly and this is could be the equilibrium temperature once hot. IOW little or no thermostat regulation"

And this is the issue myself and others are reporting and not just from one supplier...

I know I stated I wasn't going to make any further comments to this thread but... I'm glad the fact that there is an issue has now been acknowledged.

I aren't going to change the thermostat unless it's leaking in future.. between this issue and the issue of the Indian made rear arms. This really doesn't inspire confidence for the future.

Well I have got a thermostat to change today as its leaking on the seam. Let's hope all goes well :}

When it's removed from the car Dave, fill it up with water and see if it really is leaking at the seam.

Simon

It is leaking on the seam by the look of it so new one going in soon

Hi Dave.
I am sure it will go as planned;) take a few photo and post them up for members to see if you have time.

I no longer have a petrol R40 or MGZT but i still purchased an housing the other day just to see what it was like cheapest i could find.
https://www.ebay.co.uk/itm/183869318315

The seams look to be welded good, as does the materials it is made of, i had a thought when i was looking at it as we know you us two bands on the straight part, which is then pushed up against the housing and the water pump end of the engine.

My thought was if they made the straight a little longer it could be pushed fully home into the housing thus making it more sturdy add that to an housing with the three lugs and it would make for a good sturdy unit as an whole.

https://i.imgur.com/AHoIbkul.jpg1

https://i.imgur.com/B9NqgMxl.jpg2

https://i.imgur.com/Fh9EnIwl.jpg3

As you can see this is where the straight fits into the housing less the clips.
https://i.imgur.com/1dblYQGl.jpg4

not very stable unless the clip bands are fitted.
https://i.imgur.com/g2NEIWxl.jpg5

Pushed fully home into the housing and it becomes very stable.
https://i.imgur.com/wQJyTmUl.jpg6

I also noticed that inside the housing is a little stop peg which when the straight is pushed fully rests against ? why is it there.

https://i.imgur.com/pgKMktIl.jpg7

I may cut this open to see what stat is inside 82c or 88c

Job done via keyhole method all bled up and perfect car back with owner now :}

Simon
Yes it was the seam leaking as I've seen so many times before

Dave