Oil in Coolant System

[moomoomoo]

Hey guys, first off I have a 240sx with a CA18DET under the hood.

I'm just wondering what are the different possibilities of oil getting into the coolant system. Can a blown head gasket cause oil to enter the coolant system? I thought it would be the coolant entering the oil system since the coolant is under higher pressure then the oil.

The car still runs fine even with oil in the coolant, but I've decided its better to fix this problem before it gets worse.

[NISTECH]

if you have an auto trans it could be the oil cooler in the radiator is leaking into the coolant area of the radiator. also the oil pressure in your car is higher then coolant pressure most of the time(when ever the engine is under throttle) coolant pressure is only about 14 psi under load and pressurized oil pressure can get up pretty high. I assume you checked your oil for coolant? if its an auto also check your trans fluid for coolant contamination.

[moomoomoo]

its actually a manual transmissionwe took off the oil cooler and it looks physicaly fine, but i'll be getting that tested to see if its working properlywe removed the whole head off the engine and the oil is fine, no coolant detected in itI just find it wierd that the oil got into the coolant and not the other way around

[NISTECH]

unusuall for it to happen but it does happen. in most cases that i have seen it it wasent a head gasket it was either poor casting of the block or head or a trans cooler as metioned above. if there are no obvious signs of crossover leak in the head gasket you may need to have the head pressure checked at a machine shop.

[s14white240]

You may check the front timing cover. I had a ka24de and the oil and coolant were mixing together, so I replaced the head gasket and had the head magnafluxed and shaved. Re-installed the head, drove down the road, Still gettin hot and mixing oil with the coolant. After we installed a new engine, we tore the old motor apart and found that one of the lower timing chain guides had broke, letting the timing chain rub a hole in the timing cover into the water jacket. Ca18 may not be the same setup, but if so you might check it.

[moomoomoo]

Hey thanks for your advice, but i doubt that happened since the CA has a timing belt!anymore possibilitieswe're goin to check for any visable cracks on the head and block but i doubt thats the situation since its only oil in the coolant and no coolant in the oil

[CanadianCoch]

oil in the coolant is one of the key signs your HG is blown. There are several ways to check, search to find them out. The easiest one i'm told is start the engine cold with the radiator cap off, and if the coolant shoots out, your HG is blown.Somethings leaking, it's probably the HG.

Dr.

[moomoomoo]

Hmm I cant do that since the head is off but thanks for the suggestion, I'll go ahead and change the head gasket cause who knows how long that head gasket has been used forhopefully that will solve the problem