Oil Contamination in Coolant Reservoirs A Guide to Prevention

In this video I go over what engine oil may look like if coolant has gotten into it and I also go over a few possibilities of how coolant ... There's evidence of oil residue in the coolant overflow tank in my 2012 Outback 3.6R. It has 150K miles, and has been dealer maintained. Transmission fluid would be physically impossible. It has to be engine oil. Oil cooler replacement is the #1 suspect given the timing. Worst case is blown head gasket. There's a kit which attaches to the cooling system. It contains a dye that reacts with hydrocarbons. Only way to tell at this point is to perform a compression and leak-down test to see if it really is the head gasket or something else. Fresh ... basically what the TSB says is that "there was an internal casting issue with the block at the cylider walls that would allow the oil and ... Engine oil in coolant! ... Yikes. Not a common issue. My suspicion would be head gasket. Did you buy this car from a dealer? ... That's bad! The only good news is that oil in the coolant is better than coolant in the oil... Expensive fix, but probably worth doing. Any car can have a head gasket fail. Usually the "O" rings in the engine oil cooler are leaking internally. Easy to repair in an afternoon. Rob. Quote. It's your oil cooler. I promise. Drain and change NOW before you build too much sludge throughout cooling system and heater core. It's going to ...