So recently when I got an oil change, they checked my other fluids and notified me that there is oil in my coolant... again.
Last year, I noticed oil in the coolant and took it to a mechanic, they checked everything out and said it was the radiator, so they replaced that and all the related hoses and the tranny cooler. Iv googled this, and it doesnt seem to be a common reason for oil in the coolant. But is it possible?
This time I took it to a different mechanic and he checked out the head gasket, and the engine block and did all the pressure tests and everything checked out... but there's still oil in the coolant (a little thin layer at the top) so where is it coming from? My new mechanic thinks it could be left over oil residue from last time cause it's so hard to get completely out, but I'm not convinced? Can I siphon it out from the top, and see if it comes back? I drive 2007 cobalt LT