Oil Contamination in Coolant Identification, Causes, and Remedies

If you have oil in the coolant reservoir, then it means you have leaking head gaskets and oil is moving into the coolant and/or coolant is moving into the oil. The oil cooler is leaking oil in the cooler system which is a common problem and the recommendation is to replace the oil cooler. The tech said he thinks it's the DSG transmission cooler since the oil in the coolant is very dark, vs the engine oil which is as clean as a whistle. Instead of liquid soap, I would use baking soda and water. I would mix the baking soda and water in a 5 gallon bucket and I would add enough ... OP? You are describing the buildup that occurs on the relatively cool walls of the plastic surge tank. Called 'Phase Separation' it is the ... Replace oil cooler. Fill cooling system w/ fresh water. Add a small(!) amount of detergent to coolant tank, run vehicle for a short bit. Drain. 2nd Generation S-series (1995-2005) Tech - Oil in coolant reservoir - It seems to be that I have oil in my coolant reservoir and I know what ... Typically it's an oil cooler failure. If the cooler wasn't properly torqued last time, it could have lead to the premature failure this go ... When a head gasket fails, oil can leak into the cooling passages and then end up in the coolant. This results in the brown sludge that can be seen in the top of ... The diagnosis was that the oil cooler was leaking oil into the coolant. The oil cooler is part of the oil filter housing. they did install a new ...