Oil in Coolant Reservoir Diagnosing the Cause, Preventing the Damage

GL 450 2007. It's still drivable. I just got an alert yesterday that coolant is low. Is this an expensive fix ? Seems to be running and idling well, temp normal. Light brown oily mousse in the radiator and overflow reservoir. Engine oil is normal. 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 most common sign of oil in cooling system is the presence of a slimy milky-brown layer in the coolant. It is likely the oil or transmission fluid is a higher pressure than the coolant, it will likely fill the radiator with oil, and not water in the transmission ... Nope there is no place that oil and water intersect besides inside the engine. You're most likely going to find that's it's: #1 blown head gasket (semi common) 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 ... Almost certainly the oil cooler is at fault if it's a td5. The heat exchanger O-rings will have gone hard/warped and be leaking oil into the coolant. Clean the coolant tank out with brake clean or engine degreaser, then follow up with dish detergent (that will remove all the oil residue). Let ... If you have OIL in your cooling system they had better be replacing the oil cooler. It is not uncommon for us to replace both the oil cooler and ...