Oil in the coolant

[ssheen]

Hi,

 

My wife's 94 Cutlass Supreme S 3100 V6.

 

The car sprung a coolant leak from the by pass hose this weekend. Easy fix, 5$. However, when I was poking around I noticed a little bit of oil in rad on the top of the coolant. The overflow bottle had what looked to be a lot of oil in it. From what I can tell the cooltant temp does not seem to be different than normal. The oil itself does not look milky or foamy.

 

I was thinking a head gasket, but if it was I would think the car would be over heating. At least my Laser did when it blew head gaskets, now I do not know. A search found mention of an intake gasket.

 

Comments/Advice?

 

 

[Robby1870]

Hmm...oil isnt milky and neither is the coolant. Thats really odd. Maybe an oil cooler leak at the radiator? Does is burn/use a lot of oil?

[White93z34]

probably the intake gaskets are shot, how many miles are on it?

 

i'd be willing to bet thats what it is.

[Crazy K]

it would be imposible for oil to leak into the coolant system at the intake... the coolant passages are at a higher pressure that the oil circulating through the open inards of the engine.

and I believe it would be the same for at the head gasket, since the 3100 has NO oil passages through the headgasket. right?

 

more likely.... the trans cooler. Run the car with the radiator cap loose.. and if out comes a bubbling crude.... (red crude) replace the radiator!

 

 

[ssheen]

Engine oil looks good. Still kind of clean, not milky, not black on the stick.

Trans fluid looks nice and red, but darkish.

Coolant fluid has blackish oil floating on the top.

 

The car has 331k KMs on it. It does not seem to use a lot of oil. Though, honestly it has developed a few oil leaks the last while. The oil (synthetic) is maybe half down the cross hatch, on 6k KMs. Time to do an oil change.

[THe_DeTAiL3R]

When's the last time you flushed the coolant?

 

I would have to agree that I don't see any way that the intake could let oil in the coolant... unless somehow it was totally FUCKED, in which you'd be seeing coolant in the oil too... even then I don't see it happening.

[ssheen]

Admittly it has been long enough that I do not remember. However, I did add some coolant to the over flow bottle not long ago, a month at the most, and do not remember the oil in it at that time.

[Guest TurboSedan]

here is the problem with 3100/3400 intake gaskets:

 

http://www.turbosedan.com/ste/3400/DSC02586.JPG

 

that caused coolant to shoot into the engine causing milkshake like oil. i didn't really see signs of oil in the cooling system, although i think it would be possible for oil to get into the cooling system ecspecially when the engine is cold (before pressure builds in the cooling system). not likely though for that to happen though, at least not from the lower intake gasket.

[ssheen]

I am going to take it to the shop to get checked out and an estimate. I will let you know how it goes

[Regal_GS_1989]

Usually oil in the coolant is a sign of a cracked block. But i would be under the assumption that the car would run like absolute shit if that were the case.

[ssheen]

A cracked block would suck.

[Canada]

I say cracked block as well......its the only way it can happen. Just don't mistake oilly coolant for dirty coolant.

 

In order for two fluids to mix, one has to be at a higher pressure than the other. Bad intake gaskets cause coolant to get into the oil......as the coolant passages are at 15 psi or so, and the engine crank case is at atmoshpereic. In order for oil to get into coolant, the oil has to be at a higher pressure.....typically an oil passageway to coolant jack situation.....or a oil to water cooler, if so equppied.

 

This kinda reminds me of an episode of My Classic Car on Speed. The one guy was racing this C3 Corvette race car and all of the sudden water comes flying out blow off on the windshield. They think its overheating or something........but the temp gauge read normal. The next shot they got the intake off...its like....duh! Something funny had to cause the cooling system to over pressurize that quickly. Think, damn it! How about a blown oil cooler? I don't know if it was trans or engine......either of which run over 50 psi in race cars. All that pressure is instantly put into the cooling system....causing it to blow off.

[ssheen]

There was no mistaking the oil in the coolant for dirty coolant. The oil on the paper towel was pretty obvious.

 

At any rate, the problem is fixed. A new rad (tranny cooler) seems to of fixed the problem. Thanks for the help.

[Regal_GS_1989]

Ok, so it was tranny fluid, and not engine oil. I would go and have, at the very least, the trans fluid and filter changed. When i was working at a tranny shop last summer, we had an APV come in that had a trans cooler leak in the rad, and the owner wanted it fixed, and the fluid changed. Needless to say, the trans fluid looked like a strawberry milkshake. If you happen to get enough water in the trans, it can cause the clutches to swell, and start to peel.

[ssheen]

Thanks for that advice. Now to find how many Liters it takes and if there is a drain plug.