Oil in Coolant Reservoir A Comprehensive Troubleshooting Guide

Subaru oil in coolant, no coolant in oil, but how and why. Happy ... WHY COOLANT IS BOILING IN THE COOLANT TANK RESERVOIR ON A CAR. Auto ... The only thing that comes to mind, is if the new reservoir cap is not venting properly, it could allow the cooling system to over-pressurize. Seems to be running and idling well, temp normal. Light brown oily mousse in the radiator and overflow reservoir. Engine oil is normal. The oil cooler is the most likely cause, like most engines, it's combined with the oil filter housing. If your repairer doesn't know this and / ... I have a 09 Beetle, my mechanic called me with my issue and it was a failed oil cooler. I had oil in the coolant and the car overheated. The ONLY place I'm finding oil is IN the antifreeze coolant reservoir. Just to clarify: 1. There is NO power loss at all. The car feels and performs great. Transmission fluid would be physically impossible. It has to be engine oil. Oil cooler replacement is the #1 suspect given the timing. 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. Oil in coolant is a leaking oil cooler. Coolant in the oil can be many many things, with the head gasket being low on the list. Coolant in the cylinder is a ... Oil filter housing gasket is common failure point and can cause this - coolant runs through there. You should also change your oil when you do the gasket as ...