Unleash the Power Troubleshooting Oil Contamination in Coolant Reservoirs

You have only 2 possibilities. The head gasket or the oil cooler/heat exchanger. It is not up to you to tell them what to do. They should diagnose the fault ... Then flush your coolant and do an oil change. If you suspect you have an issue with your head gasket, do a compression check. Check your hoses ... 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! GL 450 2007. It's still drivable. I just got an alert yesterday that coolant is low. Is this an expensive fix ? 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 ... The coolant reservoir was leaking a brown liquid. I guess this is oil and i have heard that means its most likely a blown head gasket. The black gunk in your overflow reservoir looks kinda like misshapen globs like what you see in a lava lamp, it may be engine oil. Usually the "O" rings in the engine oil cooler are leaking internally. Easy to repair in an afternoon. Rob. Quote. Worst case is blown head gasket. There's a kit which attaches to the cooling system. It contains a dye that reacts with hydrocarbons. I inspected my engine to find watery oil on the outside of the air intake and abs brake module (behind the coolant reservoir). A quick check of ...