oil in coolant fill bottle

[Wylde_Katt]

I have a 1994 RS with approx 87000 miles on it. Problem is there is oil in the fill bottle for coolant. There isn't any oil in the antifreeze, but it is using oil. When I bought the car we didn't notice this at first. It has been drained (the fill bottle) and refilled. Took a few months but there it is again. My question is how in the world can oil go in there? My dad builds and races stock cars and I've got him stumped. No check engine light, or oil light comes on. I have a secondary issue but thanks to reading thousands of threads I think we may have discovered the answer (TCC). Any ideas would be greatly appreciated.

[drhillier]

I would start with checking your air filter and your intake system for oil as well. if oil is present, it is probably your pcv valve, or you have excessive blow by and your pcv can't keep up with it. as far as oil in the resevoir, I can only think of one thing off hand and that would be the head gasket. oil floats on water, so when your system builds up enough pressure to open the pressure spring on the cap, the oil will be on the top and be the first to end p in your bottle. has it been overheated? aluminum heads bend very easily when hot. hope that it's something really stupid and simple.... but I can't think of anything. good luck!