Oil in coolant, but don't see coolant in oil?

[turbosam6]

I ran one pass this weekend, no knock, 8 gallons of 116 in the car. That was saturday. Last night I went out to do some general maintenance on the car, and when I pulled the radiator cap, there was oil floating on top of the coolant. It is for sure oil, not rust or dirt. Its slippery and my coolant system was SPOTLESS before saturday. I pulled my dipstick, expecting the worst, but its clean. Car runs the same, no smoke. I am going to drain the oil tonight to check it, but it looks brand new on the dipstick. Plugs look brand new also. I put them in right before the race, so they got one pass and like a few street miles on them. What did I do? Everyone says "don't worry". Bull$*#t. It is wrong. Oil should not be in your radiator. And I don't have my oil cooler in there anymore, so its from the motor. Ideas? Going to do a compression test, too. What should I look for? Thanks!

 

[TX87GN]

Could be that the oil cooler lines that are in the radiator busted and leaking into the coolant that way. Just a thought. HTH's.

John C.

 

[MSDGN]

Do you use RMI?....I have seen what looked like oil in my radiator and it was the crap RMI cleaned out of the cooling system...the stuff was floating there when I removed the rad cap...

 

[turbosam6]

The oil cooler lines aren't there anymore, its a CAS aluminum radiator. I flushed the cooling system pretty good, and the coolant looked great until this. We did a leakdown test, all good. I do have some bubbles in the radiator when the car runs for a minute. All the plugs look the same. Still no smoke when running, oil still clean. Can the intake gasket cause this?

 

[GNVAIR]

Crack your oil drain plug open. If you have any coolant in the oil, it will be the first thing to come out.

 

[turbosam6]

You know what? I may have been wrong. MSDGN, you may be right. I did a leakdown, all good. I cleaned the stuff off the top of the coolant, and it appears to be OK. I was wrong about the bubbles, it was just the coolant kinda spewing out while it was running. The oil is clean, but I got a clear plastic tub to drain it into tomorrow. I am paranoid, I think. If the leakdown numbers are OK, then the head gaskets must be fine, right? Thanks so far, I'll keep you posted.

 

[turbosam6]

Oh, and I am using RMI-25, but I flushed the cooling system real well before using it. I guess if it is oil it will come back again.

 

[azgn]

one other possibility is you are blowing by the headgasket into a water passage.....usually when this happens, your overflow will have a lot of coolant and your rad will be a bit low

 

[Quick6]

I saw the same thing after using RMI and had the same reaction.

 

[Gary]

Just bought a car and after owning it for a week I decided to check the water level. I felt real bad when I saw what looked like a couple of gallons of milk in the radiator. And like you, when I pulled the dipstick it was clean. I removed the engine oil cooler first then I removed the t-stat, bottom radiator hose and the top one also. I stuck the old garden hose down inside the top hose and flushed the block for about 10 minutes. All is well now. When I told a friend about it he informed me that some people use a "water wetter" made by JB. Guess what color it is, right, it is white. I believe this was what was in my radiator as i have put over 200 miles on the car since and all is well.

Gary

 

[Steve Wood]

Probably the scum that the RMI loosened out of the water passages