Quote:
Originally Posted by shimmy
Ok the facts as I see them...
1. Oil temp rises to 2/3
2. Then water temp rises to 3/4 and then on to red slowly
3. Only happens at full throttle,
4. Initially happens only on warmer days
5 Only on Trackdays (presume this coz 100%throttle uncommon on road)
6 Off full throttle temp of water drops quickly
Mine happened last at Snett, then started to run badly at higher revs, then diagnosed as failed HG between cylinders 5/6 worse and others.
Now question is does the HG failing and leakage between cylinders cause the engine oil temps to rise OR does something else cause the oil to rise and then result in a failed HG cause of raised engine temps?
Now as Oil temps rise first noticably I think this means that the engine is getting hotter before the water temps are, so therefore the water cooling system can't be at fault.
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shimmy, I am no pro but the family biz is bmw cars.
I have seen in the past many issues in BMWs that started with the viscus fan or water pump.
As lawsy said, then it's a chain.
I don't want to doubt what you are saying, but I find this strange.
Lawsy says :
>>
The hg can fail between the 2 cylinders which increases cylinder temps, which in turn will increase water temps. Which in turn can then cause the HG to fail more so, its a viscious circle.
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Why if we have compression loss between 2 cylinders, the temp rises ?
I would expect the knocking sensors will detect this and adjust the ignition and injection.
The car would run very poorly etc.
I will take out my spark plugs today and also run the diagnostic to see for any strange knocking/compression values between the cylinders and update you.
PS : I am not rulling out the HG but at 84k km and always using good fuel, low env temperatures, never had a knocking failure and the water temp decreasing after stops from the autobahn, I find it unlikely that my car has a HG issue