molinjhar

I've had her forever and beat her to death, she's never let me down. 8 cyl motor all stock. Last Friday I noticed the radiator overflow looked funny so I looked down in it and it looked and smelled like used motor oil, not oil/antifreeze mixed but straight oil. I checked the oil in the block and it was clean. I checked the antifreeze and it was clean. Thought my son might have added oil to the overflow by mistake, and cleaned it out. Drove it to work and checked it again and found oil in there again. This has me stumped. Clean oil, clean antifreeze, good oil pressure, not overheating but I'm getting clean oil in the radiator overflow. I would think it's the head gasket but I dont have the brownish milky oil or antifreeze I've seen in the past on other vehicles with a cracked head or blown gasket. A buddy of mine asked a mechanic he knows and was told that theres a seal on the underside of the intake that causes this but I dont see how that could be. I mean how does oil get to tha overflow without mixing with the antifreeze. Has anyone seen this or have any ideas?

trucker

You could have blown head gasket where the oil goes to water jacket, but I would check if it is motor oil or transmition fluid.

1DeadZJ

Oil is lighter than water so it will get pushed into the overflow first which is why you don't see it in your radiator. I'm thinking it could be transmission fluid since the tranny cooler is inside the radiator. If it develops a leak then transmission fluid goes into your coolant and the real bad part is that coolant goes into your transmission.