Oil-Free Water Coolant Achieving Optimal System Performance

water/antifreeze in the oil is almost always a head gasket. if they drained the antifreeze and didn't fill it then i'd say they are liable. Since oil pressure is higher then cooler pressure, the slightest leak in the oil cooler will enter the coolant. Since oil floats on top of water ... If you have oil mixed with coolant in the reservoir, you will notice a thick, milky or gravy-like substance that is a tell-tale sign that you have this issue. Check oil cooler or areas where coolant and oil channel closely. Had oil in coolant once- was the oil cooler gone kaput. Was a different engine ... (flushed cooling system with 16L of coolant after the repair, ran tons of water through the reservoir) Replaced the radiator, thinking that ... The only thing I would caution is the coolant would need to be flushed, probably with a dish washing detergent like cascade to get the oil out, ... The oil always ends up in the overflow. It floats on the coolant, so it's the first to get pushed out into the expansion tank when the motor warms up. For coolant to be getting into the oil I'd say you've got a bad oil seal #8 on the oil pump/water pump shaft. Under the oil fill cap there was that light brown stuff that forms when oil and water come together. Also drained the water from the coolant ... Because, that's the only part of the car where the oil and coolant can easily intermix if there's a failure, that can easily be replaced. Any ...