Oil in the coolant, but no coolant in the oil.

azbanks · azbanks's Garage

I put in a replacement engine for my 1990 S2 and i am getting oil mixed in to the coolant.
I am not getting coolant in the oil(which is good since I had to drive the car home from LA to Phoenix).

Has anyone had experience with this and can point me in the right direction.

I am hoping it is just something in the oil filter/thermostat housing. If it's not that, my second(and less popular) guess is the head gasket.

I want to get this figured out and fixed and then flush the coolant system a few times.
I have a brand new CSF radiatior and a brand new coolant tank to install and I don't want to contaminate them with oil.

azbanks · azbanks's Garage

Nevermind. A quick search gave me the answer I was looking for.

walfreyydo · walfreyydo's Garage

Try the oil cooler housing seals first

wwdwgs · wwdwgs's Garage

walfreyydo,
I would assume that all the seals and "maintenance" items (o-rings etc) were supposed to be either checked or replaced when the engine (replacement) was out. Replacing coolant-oil radiator gaskets and o-rings on the engine is a nice task.

azbanks · azbanks's Garage

I checked them all and replaced most of them. I guess I should have replaced them all when the engine was out.

I bought a new full replacement kit and will be replacing them all this time.

walfreyydo · walfreyydo's Garage

Quote:

Originally Posted by wwdwgs

walfreyydo,
I would assume that all the seals and "maintenance" items (o-rings etc) were supposed to be either checked or replaced when the engine (replacement) was out. Replacing coolant-oil radiator gaskets and o-rings on the engine is a nice task.

The OP never said if this was done or not and that is one of the main causes (and easiest to address) of oil/coolant mixing. If this was done, and confirmed not to be leaking, then there are unfortunately, bigger issues (head gasket)

Here is a good video of the process:
https://www.youtube.com/watch?v=5zZLHAqXxwM

azbanks · azbanks's Garage

Looking back, I was in a rush to get the engine in in time for RSR so I didn't check/replace the oil cooler seals.

They are all replaced now and surprisingly, it is going back together easier than it came apart.

It will be back together in time for Phoenix Flight and UnStock.

azbanks · azbanks's Garage

Is it possible to replace the inner o-ring on a late/one piece OPRV?

wwdwgs · wwdwgs's Garage

Yes.

azbanks · azbanks's Garage

I put a new water pump and thermostat on before I put the replacement engine in the car so those are good.
I put on a new oil pan gasket and ran the first oil through the replacement engine for 500 miles and did an oil/filter change just to be safe, so all that is good.

azbanks · azbanks's Garage

The general consensus was that is was most likely the oil filter housing seals and unlikely to be the head gasket.
I replaced all the oil filter housing seals and guess what...

I am still getting oil in the coolant.
Time for a new head gasket.

Monkey Wrench · Monkey Wrench's Garage

I tried the stuff in a can in my old volvo 240 to see if it worked, It did not but when I replaced the headgasket I could see it was trying to plug the leak. Mostly it is frowned upon but maybe it works if the leak is caught soon enough. there are several types.. I used the one that requires you to drain the water and then flush the water then replace antifreeze. Bar's stop leak does sell the stuff on a continuing basis in more than one flavor. I'm sure there are cases where it worked, it did not for me, waste of time ? Yes maybe..

Im sure people do that and then sell the car, is it permeant? will it plug up the rad? maybe?

where id use it is when you have a car with a blown head gasket that isn't worth the cost of a head gasket replacement, Just before you call the wrecker to scrap it.. , then there is not so much to loose. or maybe if you were in some remote location , it may get you home.

there is stuff you can add to the rad water, that stuff is compatibvle wiht the coolant and you can leave it in there a while. I dont think it works as well to fix a leak. I guess you could add that if you had success, as insurance.

maybe whether it works depends on the type of leak mine was combustion chamber to exhause so I had steam out of the exhaust, steam that smells of coolant. it might be possible to have a different type of leak..

I've head of sticking a CO meter in the water bottle in theory the presence of 02 inthe water bottle is not normal but if exhaust is entering it may.. so its perhaps a way of detecting it. a mechanic that owns one may know more about doing that.

a symptom I noticed was that the water level varies it can push all the water out of the head and cause an over heating condition. basically the water boils in the head, then head may warp. so I'd watch if you have water level fluctuation and watch your heat gauge carefully.

best way is probably just to go ahead and decapitate it , see how things look, big job though. I hope you have success.

walfreyydo · walfreyydo's Garage

You may want to try a coolant pressure test, as this will hopefully tell you if you have a pressure leak before throwing all your chips at the head gasket assumption (albeit a fairly good one). A faulty head gasket would/should leak pressure into the cylinder.

I would also mention if you are taking the head off anyways, consider getting a valve job done, valve seals replaced, guides checked, etc.

Once you get the head off and if you can confirm a bad HG (hopefully you should be able to see where it failed), you should 100% get the head resurfaced, and so it would make sense to do the rest of these "while you are in there" tasks done at the same time while its at the machine shop.