2000 A8 Oil Cooler
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2000 A8 Oil Cooler
Just pulled oil cooler and disassembled. Can anyone explain to me why any of the internal o-rings leaking would cause oil to enter coolant system. It looks like either coolant or oil leaking from these rings would never be able to flow into another fluid orfice but would leak into the inner housing and then out the weep hole.
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Leaked oil clings to the sealing plate and creeps around coolant O-ring?
Like you, I'd expect any large, flowing leak to come right out the housing.
But I also changed these O-rings six months ago and the brown oil scum on top of the coolant in the tank has not recurred.
I guess the next question would be: if leaked oil has migrated across the sealing plate to come into contact with a coolant O-ring, are there circumstances in which it can get past the coolant O-ring?
Empirically we know the answer is yes, but I don't know enough about how O-rings behave across the possible temperature and pressure ranges to say whether that's truly unexpected.
Tom
But I also changed these O-rings six months ago and the brown oil scum on top of the coolant in the tank has not recurred.
I guess the next question would be: if leaked oil has migrated across the sealing plate to come into contact with a coolant O-ring, are there circumstances in which it can get past the coolant O-ring?
Empirically we know the answer is yes, but I don't know enough about how O-rings behave across the possible temperature and pressure ranges to say whether that's truly unexpected.
Tom
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Re: Leaked oil clings to the sealing plate and creeps around coolant O-ring?
I agree Tom, it has to be an o-ring. The coolant was loaded with sludge and I expected to find a simple cause when I seperated the exchanger. I did run low pressure hot water in the oil side before seperation and found a small drip in the coolant side. I also put a dye in the exchanger after seperation on the oil side and found no leakage through to the coolant half of the exchanger.
If I had any doubts, I would spend the money on a new housing or exchanger. This has been fun but my fun meter is just about pegged.
If I had any doubts, I would spend the money on a new housing or exchanger. This has been fun but my fun meter is just about pegged.
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