Oil cooler seals

Ghetto914 · 06-05-2007, 06:50 PM

So i got a phone call the other day, and I am starting to think that instead of a blown headgasket, my oil cooler seals may have gone. Before i shut off my car, i never saw any white smoke, or felt the engine running rough.

Does the oil cooler actually have coolant running through it? is it possible that all of my coolant mixed into the oil through the cooler?

And were this the case, what would i need to do? I figure i'd need to completely change the oil, oil filter, coolant, maybe do the radiator hoses, new oil cooler seals, i needed to do the thermo fan switch anyways....

Would having milky oil for maybe 10-20 minutes of driving time at highway speeds be cause for me to do more internal work?

ERAU944 · ERAU944's Garage

yes absolutely it is possible, not only is it possible but it is very likely, especially on model year '87, what year is your car? you need a special tool to line up the housing so that the oil pressure relief valve doesn't bind, new seals, and a coolant and oil system flush. my friend had OCS fail on his '87 and drove for definitely more than 20 minutes, flushed both systems and changed the seals, and he was on his way. i'd say you're good to go with system flushes, and new seals.

myskyon · 06-05-2007, 07:12 PM

ok now i am confused my oil cooler on my 87 951 is seperate from my radiator so there is no way my oil could mix with my coolant through my oil cooler. i am not under standing what you are talking about. could you provide some more information ERAU944.

Ghetto914 · 06-05-2007, 07:44 PM

Mine is an 86. one of my other threads "tough engine situation" has the lowdown on how it went down...

I assume that pelicanparts has the oil relief valve thingy that i need?

Any help putting together a guide to what order to adress things in would help. thanks.

nize · nize's Garage

the oil cooler is not where the oil/coolant can mix, that occurs in the oil filter housing. the same thing happened to a buddy's car, and he now has to replace his rod bearings due to rod2 knocking.

the porsche shop manual states if coolant ever mixes with oil, replace the rod bearings.

AaronM · 06-06-2007, 04:12 PM

Quote:

Originally posted by nize
the oil cooler is not where the oil/coolant can mix, that occurs in the oil filter housing. the same thing happened to a buddy's car, and he now has to replace his rod bearings due to rod2 knocking.

the porsche shop manual states if coolant ever mixes with oil, replace the rod bearings.

Peter, the 951 uses a different oil cooling system than the 944 NA.

The 944 NA has a heat exchanger where the oil cooler is integral to the engine block and is surrounded by coolant. If a seal in this blows out, the oil and coolant mix.

http://www.connactivity.com/~kgross/FAQ/944faqoc.html

nize · nize's Garage

okay, then why is this guy asking about n/a stuff in the turbo forum ?

go post in the right forum and you'll get the right answers !

Ghetto914 · 06-06-2007, 05:48 PM

Okay now i'm confused.....

86 951, where can the oil mix with coolant aside from the head gasket going?

and is it 100% true i have to do the bearings if my coolant and oil mix?

nize · nize's Garage

read my earlier post;
oil and coolant can mix on a 951 in the oil filter housing.

the only thing that's 100% true is that the porsche factory shop manual states if coolant ever mixes with the oil in the motor, you must replace the rod bearings.

this is probably just a precaution, but so far it's turned out to be true from what i've seen happen firsthand.

Ghetto914 · 06-06-2007, 11:16 PM

Great.. there i was thinking i wasnt going to have to do a motor swap.....

seems to me that either way, im gonna have to spend a bunch of money here. if i just do the oil, filters, radiator hoses, etc then the bearing will peobably explode, meaning dead engine, or im gonna have to replace the motor instead....

there went my happy day......

JustinL · 06-07-2007, 07:14 AM

I think it's still more likely a head gasket problem. When the oil cooler housing seals go you usually get oil in the coolant but not coolant in the oil because the oil pressure is much higher than the coolant pressure.

If you drove with milky oil, then your bearings life has been shortened dramatically. You can put it all back together with new gaskets and it will run, but not for very long. When it does let go it may go with a bang and be a lot more expensive.

Just my 2c YMMV

Justin

AaronM · 06-07-2007, 08:59 AM

Quote:

Originally posted by nize
okay, then why is this guy asking about n/a stuff in the turbo forum ?

go post in the right forum and you'll get the right answers !

I need to remember which forum I'm in. Doh!

Peter's absolutely right, if coolant got into the oil, you really should replace the rod bearings.

Porsche-O-Phile · Porsche-O-Phile's Garage

Do you have coolant in the oil or oil in the coolant? There's a difference.

If you get coolant in the oil, yea it might be a good idea to replace the rod bearings, though probably not necessary. If you only have some oil in the coolant (the "milkshake" scenario) you can flush the coolant system (it makes a helluve mess with all that stuff glopping out of there) and put everything back together.

You could always "just try it" once you have fresh oil in there to see if it works. If it does without problem, congrats - you just saved many hours of labor and a couple hundred bucks. Worst case is one goes (most likely #2), you spin the bearing and have to replace the bearings anyway.