[Sam_M]

Perfect example of computer based analysis vs old school analysis.

[Nel2014]

Hopefully they will fix it today

[salimshk]

Nel did you sort it mate?

As for me BMW kept my car for two days. In the end she came back and said we need another two hours to diagnose the problem. I asked have you checked the thermostat yet? If so, how have you determined that there is no problem with it?

She comes back after a few hours to say we need to take the stat off the car to test and if the stat is found not to be at fault it will be £350 labour to refit the stat!!! After two days of fucking around they hadn't tested the bloody thing it went it for.

She got an earful and I insisted on taking my car back. The good thing is I got a pressure test done (found no leaks) and system bled properly from BMW for free.

Bad thing is, I still have the bloody problem and the coolant temp is now not going past 75c.

So, we know so far that there is no air in the system. There are no coolant leaks. It is unlikely to be the EGR stat. If it is not the main stat could it be the water pump?

Also, I'm going to take the stat off myself and test it but how do I know if it is working correctly. I understand I have to put it in hot water but if the coolant is staying at 75c that suggests its not closed properly in the first place right?

[Silver Streek]

Fairly easy to test, you do need a thermometer tho. Tie the stat to a wooden spoon or something so that you can suspend it in a pan of water on your cooker. If it touches the bottom it will heat up from metal to metal contact. As the water heats up look to see any movement as the wax expands to move the plunger then note the temp when it starts moving. They shouldnt open before 88 degs. If your cars diesel (sorry I forgot) the stat will be an 88 to 90 deg stat. Not sure if petrol stats are the same. Ideally you need a new one so you can compare the two to see if the stat you have is in the fully closed position when its cold too.

[Nel2014]

Originally Posted by salimshk

Nel did you sort it mate?

As for me BMW kept my car for two days. In the end she came back and said we need another two hours to diagnose the problem. I asked have you checked the thermostat yet? If so, how have you determined that there is no problem with it?

She comes back after a few hours to say we need to take the stat off the car to test and if the stat is found not to be at fault it will be £350 labour to refit the stat!!! After two days of fucking around they hadn't tested the bloody thing it went it for.

She got an earful and I insisted on taking my car back. The good thing is I got a pressure test done (found no leaks) and system bled properly from BMW for free.

Bad thing is, I still have the bloody problem and the coolant temp is now not going past 75c.

So, we know so far that there is no air in the system. There are no coolant leaks. It is unlikely to be the EGR stat. If it is not the main stat could it be the water pump?

Also, I'm going to take the stat off myself and test it but how do I know if it is working correctly. I understand I have to put it in hot water but if the coolant is staying at 75c that suggests its not closed properly in the first place right?

Hi, I'm still having issues with it. Car gets to 85 -87 sometimes and cruising can go down to 82-83 degrees.
My heater is blowing cold from time to time. Was thinking of draining, refilling and bleeding coolant again. Also will take thermo off to test as said above.
However the car drives absolutely fine, very smooth no issues at all. Maybe we had a bad batch of thermostats?

[salimshk]

Originally Posted by Silver Streek

Fairly easy to test, you do need a thermometer tho. Tie the stat to a wooden spoon or something so that you can suspend it in a pan of water on your cooker. If it touches the bottom it will heat up from metal to metal contact. As the water heats up look to see any movement as the wax expands to move the plunger then note the temp when it starts moving. They shouldnt open before 88 degs. If your cars diesel (sorry I forgot) the stat will be an 88 to 90 deg stat. Not sure if petrol stats are the same. Ideally you need a new one so you can compare the two to see if the stat you have is in the fully closed position when its cold too.

I thought I would test the old one before taking the one in question off the car. So the stat opens in hot water and closes in cold water.

I do no understand what we have established from this though. Surely, the one on the car is opening and closing to some degree thats why the water is staying at around 75c. I'm guessing it just opens slightly less or more than its supposed to

[salimshk]

Originally Posted by Nel2014

Hi, I'm still having issues with it. Car gets to 85 -87 sometimes and cruising can go down to 82-83 degrees.
My heater is blowing cold from time to time. Was thinking of draining, refilling and bleeding coolant again. Also will take thermo off to test as said above.
However the car drives absolutely fine, very smooth no issues at all. Maybe we had a bad batch of thermostats?

Maybe we should write to Cotswold together and take it from there. Can't be a coincidence that we both have the same symptoms and we have definitely ruled out coolant or air locks on mine seeing as that BMW themselves have bled and pressure tested it.

[Nel2014]

Yours is a 330d right, do you know what the part number is?
If different code they are probably very similar - it does seem like a bit of a coincidence to me.
Replaced waterpump and aux belt everything else is working fine.

[salimshk]

It is indeed.

Part No: 1151 7805 811. Same parts have been replaced on mine too

[Nel2014]

Mine is 11518512234 so slightly different

[Nel2014]

I was looking at coolant vacuum kits to try and get rid of the airlock.
But I am still unsure if the stat is faulty ... 🤬
I think you have probably ruled out and airlock or leak when BMW did pressure test so I thinking stat must be more likely. When you test it you will know for sure.

[Nel2014]

I'm going to try fitting new thermostat this weekend, drain and full bleed process this weekend to try and sort it..¤

[Chappers 71]

It may be the EGR stat that's faulty

[Nel2014]

It doesn't have thermostat on mine just valve and egr cooler.

[Silver Streek]

Originally Posted by Nel2014

It doesn't have thermostat on mine just valve and egr cooler.

Are you sure?? I though all post EU4 emissions egr coolers had stats.

The stat looks very different to the main stat, the egr stat is long and thin, and held in place by just 2 bolts.

[HighlandPete]

Originally Posted by salimshk

Maybe we should write to Cotswold together and take it from there. Can't be a coincidence that we both have the same symptoms and we have definitely ruled out coolant or air locks on mine seeing as that BMW themselves have bled and pressure tested it.

Quickly scanning the posts, is the temperature stable when the heater is not demanding heat? 88 - 92 C range?

Second question, is the car MT or AT? AT has a third thermostat in the coolant system for the autobox cooler.

[Nel2014]

Originally Posted by Silver Streek

Are you sure?? I though all post EU4 emissions egr coolers had stats.

The stat looks very different to the main stat, the egr stat is long and thin, and held in place by just 2 bolts.

Hi,
Mine is the n47 lci engine, the M47 engine had the egr stat on the top of cooler held on by 2 bolts i believe. However n47 doesn't. So I guess you would have to replace the whole thing if there is a problem with that...

[Nel2014]

Originally Posted by HighlandPete

Quickly scanning the posts, is the temperature stable when the heater is not demanding heat? 88 - 92 C range?

Second question, is the car MT or AT? AT has a third thermostat in the coolant system for the autobox cooler.

Temps do not seem to be effected by heater. Generally is blowing cold air at the moment. Usually I get to 85-86 C. If set the blower nearer max setting it gets warmer
Mine is manual transmission 320d n47.

[salimshk]

Originally Posted by HighlandPete

Quickly scanning the posts, is the temperature stable when the heater is not demanding heat? 88 - 92 C range?

Second question, is the car MT or AT? AT has a third thermostat in the coolant system for the autobox cooler.

It's not going over 75 ish now regardless of temperature of heaters inside the car. It's an AT.

How do I check the thermostat for the gearbox? Where is it located

[HighlandPete]

Originally Posted by salimshk

It's not going over 75 ish now regardless of temperature of heaters inside the car. It's an AT.

How do I check the thermostat for the gearbox? Where is it located

Low temperature like that can be the oil cooler thermostat. Problem is it is part of the oil cooler.

It is down near the bottom of the radiator, passenger side. Never had to do this myself, as my issues were minor, solved with EGR thermostat and completely sorted (~90C) with the main thermostat. A bit of hose clamping may be needed to temporarily stop the flow back to the bottom of the radiator. I'd start with the Tee'd off hose that drops down and onto the oil cooler.

Same issue as an EGR thermostat failure, coolant by-passes (short circuits) the main coolant circuit. There is enough flow to prevent the ECT climbing in typical load conditions.

[Nel2014]

Thermostat changed today and coolant re-bleeded, still the same problem

[salimshk]

Originally Posted by HighlandPete

Low temperature like that can be the oil cooler thermostat. Problem is it is part of the oil cooler.

It is down near the bottom of the radiator, passenger side. Never had to do this myself, as my issues were minor, solved with EGR thermostat and completely sorted (~90C) with the main thermostat. A bit of hose clamping may be needed to temporarily stop the flow back to the bottom of the radiator. I'd start with the Tee'd off hose that drops down and onto the oil cooler.

Same issue as an EGR thermostat failure, coolant by-passes (short circuits) the main coolant circuit. There is enough flow to prevent the ECT climbing in typical load conditions.

Thanks Pete. Did a bit more research on this and sounds like you're onto something. Issue is a made a big fuss at bmw and they agreed to change my thermostat next week for free!