Kv6 new thermostat leaks?

[kaiser]

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

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.

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

Maybe you would care to explain?

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.

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.

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?

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.

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.

Well I have a special link just for you!! 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!!

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..

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:

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.

18 degrees?
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!

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!
Standing with an overheated lump waiting for the AA is not my idea of fun!
__________________

[vitesse]

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.

[kaiser]

Originally Posted by vitesse

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!

[biffa75]

"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.

[dave lincs]

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

[SD1too]

Originally Posted by dave lincs

Well I have got a thermostat to change today as its leaking on the seam.

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

Simon

[dave lincs]

Originally Posted by SD1too

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

[Arctic]

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.

1

2

3

As you can see this is where the straight fits into the housing less the clips.
4

not very stable unless the clip bands are fitted.
5

Pushed fully home into the housing and it becomes very stable.
6

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.

7

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

[dave lincs]

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

[dave lincs]

Originally Posted by SD1too

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

Simon

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

Dave