Thermostat?
 

Battery was playing up recently i.e not turning over unless jump started.

Happened again today at work so i sat there for 20 mins in the car with it running then i see loads of steam under the bonnet. Lift it and its hot as hell and its leaked and sprayed a bit of anti freeze and water everywhere and leaked loads under the car.



Called AA and he got rid of the pressure by blowing some liquid out of this pipe which connects to the heater container what holds the water and he noticed that when he accelerates by touching the thing under the bonnet, the water rises in the container and when he stopped, it would sink again. And the water gets steaming hot and creates a lot of pressure under the cap hence the steam and liquid spraying a little bit.



He mentioned it could be the thermostat thats gone?



I have an MG ZT v6 engine car..2003..any idea if it is? And how much are we talking?

And the fan i think is ok cuz the heater in the aircon inside the car is good.

Garages are charging me 500....

This was yesterday btw. I drove to the garage and it seemed fine..started up straight away, garage is 10 mins away but the temp stayed on middle..still a thermostat issue?

Take top cover off, look into the V of the engine with a torch, check for signs of leakage (will be stained pink from the OAT antifreeze)

Parts are around £50 if you want to fit yourself.

Very possibly, and do not allow garage to jump to the automatic head gasket failure diagnosis. The thermostat housing is plastic and can split.

However you must also check for correct operation of your cooling fan. If that has failed it may have contributed or caused the overheating in the first place.

Do not rely on the temperature gauge for meaningful info.

As above you need to know that your cooling fan is working, start the car and press the demist button, the fan should operate. Next thing is to use obd to monitor the coolant temperature, do a search on here for the how to.click here http://www.the75andztclub.co.uk/foru...ated+clarified

Check water level, and check often, when cold. I think your fan is not working. If thermostat, it would be a problem at all times, this seems to be only when stationary.

And what is the garage charging you 500 for??

The fan we are talking about here is the fan in the engine bay. Has nothing to do with the heater fan.

How do you take it off? / easy to put back on?


Started steaming up under the bonnet when I was stationary for 20 minutes charging my battery after a jump start. Thats the first time I noticed any steam. When I checked the water level, first there was a lot of pressure built up and it was still extremely hot, but there was no water in the yellow radiator container. I suppose the puddle under the car is where its gone..

How would I check to see if the fan is working properly?

Garage is Wigg in Beccles.

I have a v6 2.5

I get told they only fail in the k series engines and not mine. I think i might have freelance?

I will do this when I get it back from the garage. I think it does work. And whats obd? :)

The garage reckon its not the thermostat but a leak as they can smell antifreeze. Surely that means nothing? Could be from the radiator cap being under pressure releasing the water and anti freeze no??

Obd is the odometer that displays your cars mileage. Start the car then press and hold the trip reset button until on/off flashes, when on press the button again and keep tapping it until number 19 is shown, wait a second then press the button until number 7 is shown. The display will then show the coolant temperature accurately.
If you turn the ignition off you have to do it again. Click the link in my other post to see t-cuts excellent information.

This garage clearly does not know the engine well, so be careful.

It could well be the thermostat - its not the actual thermostat that sticks, but as already mentioned the thermostat housing that bursts, causing coolant loss.

However as has been pointed out, you must check the operation of the cooling fan - it could be failure of this which is leading to problems.

Take it step by step:

1. Is the cooling fan working?

2. Where is the coolant leaking? If not the expansion tank, remove the 2 bolts that hold the engine cover on (the part that says V6 on it) and shine a torch down the V to see if there is coolant leaking or stains. If so then the thermostat housing has almost certainly split.

This is the kit you will need:
http://www.ebay.co.uk/itm/BRAND-NEW-...item20d9a80836

Do not guess but check carefully!:)

The cooling fan did kick in once AA did a few things to it.

Nothing to do with my problem right?

http://www.the75andztclub.co.uk/foru...d.php?t=161740

Is the thermostat that difficult to get to? What I mean is, when they say 8 hours worth, serious? I have a v6 and apparently the airbox has to come out too..?

Sam, to check the cooling fan is working correctly:
Start the Car

When you are sat in the car press the front screen demist button ( just below the radio on the centre console)

Get out of the car and go around to the front of the bonnet and look through the grill between the headlights.

The large fan behind the grill should be running continuously.

If not then you do have a fan problem. This may not be the only problem but it does need fixing

There are a few ways to do this, all of which involve dismantling the front of the car, reading your posts so far this may not be something you wish to tackle yourself. Seek out active members on here that are close to you and they will be able to guide you to the correct person to complete your repairs and at the best cost ;)

The thermostat sits on the bottom of the V:
http://i1054.photobucket.com/albums/...t/952284E1.jpg

8 hours labour is over the top. Yes the air box has to come out - a 10 second job as it just pulls out of rubber mounts! Do not let the garage over state the job.


However the fact that the cooling fan worked "after it was fiddled with" does not sound good, it needs to work promptly and reliably. You have to understand how it works:

The fan runs with either 2 or 3 speeds. When engine temp rises low speed will cut in which is usually enough. However fan also runs on low speed when the aircon is switched on, so after some years, low speed will wear out and fail first. That's why we are suggesting checking if it runs when operating the aircon - if not then there is a problem which must be fixed.

If low speed has failed then the engine will get hotter and hotter, until eventually high speed emergency will cut in, however by then it is on the threshold of danger. This can lead to the coolant boiling and overflowing, even with the fan running. This is why a faulty fan could be the root of your problems, and why it must be checked.

Understand also that the temperature gauge is next to useless - it is designed to remain still between 75 and 112oC, so when it does finally rise it is often too late. It may as well be painted onto the dial.

Carry out the check indicated by Stocktake above, and post the result. The V6 cooling system works perfectly well if all the components are in good condition, so once the fault is found and repaired you will have no more issues. Blind guesswork however will lead to disaster!

Alternatively, if the cooling fan is working correctly following your tests, then follow the advice given already and check for coolant in the engine V, a sure sign the plastic thermostat housing has split and is leaking.

Thank you so much for these guides! I will test the cooling fan when I get the car back..theyve had it for 22 hours..

Update!

Garage done a pressure test and it seemed to be leaking water from the cooling pipes. Apparently its corroded in. I think I need 2 of these? And also a silicon hose with bleed screw/valve.

I was told to find a kv6 metal cooling pipe if I could as John Grose may not be able to get the parts.

I was quoted 77 for cooling pipes and 41 for silicon and 80 for labour.

He doesnt think its the thermostat because theres heat in the car and its leaking water from the pressure test.

He said the pipes are like the letter L?

Could the pipes be the issue then?

Leaking pipes certainly won't help, but a scattergun "replace em all" approach seems a little over the top.

However you are currently at the mercy of the garage. Dependent on the year of your car, the metal coolant pipes may be unavailable, however some owners have simply replaced them with new lengths of hose.

If pipes are leaking could it still be the thermostat

Cuz if the water is leaking, why would we say the thermo is caussing the overheat?

Or is it possible that with the thermostat going it could have damaged the cooling pipes?

:drunk::drunk::drunk::drunk::drunk:

If you are loosing coolant than that will almost certainly cause overheating. I had the same issue with the lower coolant pipes. In had to buy second hand ones. Be warned that there are two types of these pipes. I'll see if i can find a picture of mine.

Thee are the pipes on my car, there is another type that have fatter pipes.

Im just hoping that the thermostat is alright and its the pipes that i need. Do you know where I can get these from?

I need a silicon hose with bleed screw, and a kv6 metal cooling pipe.
Although is my engine even a k series? I thought k series was the older engine? :/

The KV6 was derived originally from the K series, although they really have nothing in common.

Doing the thermostat is not a disaster, its even possible to replace it without removing the manifolds.

Here is the thermostat with 2 of its outlets showing...
http://i1054.photobucket.com/albums/...t/761614AB.jpg

But unless you have seen the offending pipes its going to be difficult to know exactly what is required.

I'.also unsure on the insistance on "silicone" pipe, there are no slicone pipes fitted to the engine.

I believe this is the pipe I need cuz he said they are welded together and have 2 right angles on it. Where can I buy this and the silicone hose with bleed screw?


But if the pressure test has failed on a leak, this is most likely the issue right? But if so, why did the radiator cap overflow with hot coolant from pressure?

Thats what you need to find out!

You or your garage will need to be really methodical about this rather than just throwing new parts at it. Find out whats gone wrong.

I would get in touch with one of the traders on here.

Agreed, something does not add up here. Shame youre not closer to me, I would take a look. Are none of the traders on here close to you?

:wot::wot::wot::wot:

With this taking place while the engine was idling, I would still be recommending a close look at the operation of the cooling fan.

I do rather feel with respect, that the OP is missing the point here - there may well be leaking pipes, but I would want to know why before I replaced anything. The coolant does not pressurise and boil over without reason.

Omg this is doing my head in :((

I will ask what is causing the coolant to boil out of the radiator cap then.

Anyone on this forum who lives fairly close?

No offense meant Brainking!:)

You might need to be pro-active and ask the garage exactly how they are reaching their conclusions.

Well they said they did a pressure test and found a leak in the coolant hose. They said it has corroded in and they need replacing. So the leak wont have anything to do with the coolant boiling over? And if the fan works behind the grill (they can only test this by linking it up to an external battery atm right..?), then it means the thermostat is stuck closed? Or will it stop once the hoses are replaced to stop the leak?

Yes ask the garage, In my opinion they need to,

If there is a leak or damaged hose replace it,
Fill the system correctly with coolant,
Run the engine and check the low speed works on the radiator fan,
Check the thermostat opens at the correct temperature.

The low speed can be tested by pressing the demist button when the car is first started.

Sam, go to bed.:bed:

Tomorrow with fresh eyes read posts 18 and 19 which tell you clearly how to test the fan.

Of course leaking pipes are a problem, and they need to be fixed as well.

Night night!:bigsmile:

I know you said u can test the fan behind the grill by pressing the demist, but at work someone said the fan which is behind the grill and the fan behind the dash are different and the dashboard fan demists the car and doesnt involve the grill fan. Is this not true?


Also we cant really run the engine for long because it will seize up if no coolant is getting to it hence leaking.

That's not true.

It won't seize if the leak is repaired and fresh coolant is put in as per my previous post.

As already explained, the fan behind the grill is also used by the air-conditioning. So when you press the demist button, the fan behind the grill should operate because that's where the aircon condenser is situated.

Ok so you would say the cheapest way to do this is like this:

Phone garage and ask despite the failed pressure test, why was the coolant boiling over?

Make sure fan is working on demist
If not, fix this.

Replace coolant pipes and silicone hose with bleed screw.
Failed pressure test anyway and coolant is leaking apparently.

If all fails still..then its the thermostat.
Replace this part and find 400 pounds for labour.


Thats a good routine or?

I would suggest in this order.

Check the pipe that runs along the bottom of the rad to as this can ro tony and perforate 😀

Need to find a trusted trader I can get these parts from :/

Thread moved to appropriate forum. Re-direct left in old.

Number 19, is that my part?

http://www.rimmerbros.co.uk/Item--i-GRID001584

If it's the lower coolant pipes that sit behind the bumper that are leaking, then yes! :)

Quoted 151 for the silicone hose and metal cooling pipe.

Inc delivery.

Sounds right??

Yip it's been change to stainless steel though

All fixed! :)

Drove for about 30 minutes and seems fine. Temp gauge stays in the middle.

I do however occasionally smell a bit of burning or something but that will probably be down to mystery as the heater isnt on. No steam under the bonnet etc. Charged 81 for 2 hours labour + VAT.

Wasnt the thermostat in the end, was just leaking hoses so the coolant was going elsewhere.

Hopefully it stays good ;)

Thanks for the update and glad it all worked out ok!

Earlier in the thread you mentioned about using a trip button to find out accurate coolant temp etc? Could you tell me more about this and what I could use it for and how to navigate through it? Thanks

Press and hold your trip button until the odometer shows test then quickly tap the trip button until you get to 19 it will then show Log_on & Log_off alternately, when it's showing Log_off quickly tap the button until you get to 7. it'll then show you the coolant temperature, do this with the engine running if you want to monitor it while driving.

Hmm im assuming my trip button is the button on the end of my indicator stick. I done this with ignition on but when I hold it, it just reset my trip distance back to 0 with Trip Distance 2. I held it on speed and my numbers were just increasing by mph every second. It didnt say test or anything

No, the trip button is the one on your instrument cluster next to the mileage reading :)

No, the one on the intruments...:)

Where -.- sarcasm? :p

Oh hang on :p

_ _ _ 000

I am stationary.

This normal?

Also on the LCD, on the Speed Limit bit, is it meant to tell me my current speed? Cuz I always get ---

No sarcasm intended my good sir, simply meant as a helpful post. Apologies if it was taken the wrong way.:bowdown:

Any idea? :/

I've attached a picture of the button you need to press.

The speed limit is to warn you if you go over the set speed limit (set by yourself by pressing the stalk button)

Yep got it. Thanks:)

And ahh ok. Thought it was a digital speedometer.

Trip Screen Diagnostic Mode: http://the75andztclub.co.uk/forum/sh...d.php?p=735128

Did you check the fan was running OK? You should make sure it is, so you don't have an overheat when sat still or damage the A/C system due to overpressure.

Matt,

Just to avoid any misunderstandings, the air conditioning trinary switch will disable the compressor if refrigerant pressure rises too high, so the system will stop operating and no damage will result.

Simon

http://www.rimmerbros.co.uk/Item--i-S3SGA02
http://www.rimmerbros.co.uk/Item--i-S3SGA03DS
http://www.rimmerbros.co.uk/Item--i-S3SGA06DS


http://www.ebay.co.uk/itm/BATTERY-CH...item25843f10c1

http://www.ebay.co.uk/itm/250ml-Holt...item19e387d256

http://www.ebay.co.uk/itm/REDEX-500m...item1e6ca198d0

http://www.ebay.co.uk/itm/Redex-Petr...item41609b3fb3


If I used all these at once, would the stuff conflict?

http://www.ebay.co.uk/sch/i.html?_od...r+oil&_sacat=0

Whats a good one for a ZT?

Could have saved 245 pounds?

http://www.ebay.co.uk/itm/SEALIT-RAD...item33861e08dd

-.-

Don't add cheap sealing muck to your engine please, it is a bad idea OK.. :}

The cooling system in your car is mainly water, and water boils at 212f 100c I think. But if you pressurise the system then it doesn't boil untill about 220f ish.. And cars cooling systems are under pressure once the engine gets hot...

So.. If you get a leak in a pressurised system running above 212f, as you did, then the pressure drops and it will start to boil, which yours did. All that is a pain, but perfectly understandable-normal.. :}

So you just need to fix the leak, and replace any lost coolant fluid.

When you select "demist" on your dash, this causes the internal heating fan to run to clear the mist, and the engine fan to run to keep the air con condenser cool. Both fans should run... OK. :}
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