1984 944 2.5 NA. So on Sunday I finished up the timing belt/water pump replacement project and everything went smooth, car ran great sitting in the garage. Monday evening when bleeding the cooling system I noticed the "milkshake" in the coolant reservoir. I pulled the lower radiator hose and the brown sludge came out. I then removed the block plug to drain the coolant out of there an it came out without any contamination. I also drained a bit of oil to check it and the oil was fine, no coolant in it. What's troubling me is when I first began the timing belt/water pump installation and drained the coolant there was no contamination. I did pressure test the cooling system at 13-14 psi and left it pressurized for about an hour before installing the belts. Is it possible to have blown an oil cooler seal pressure testing the system? Should I just plan on pulling the oil cooler and replacing the seals?

 

Yes. And yes.

See the recent thread on cooler seal replacement for some good information.

 

Sounds good. Guess I'm doing the seals. Was looking at the alignment tool on pelicanparts just now. Not too expensive (around $32 with shipping) but there is also one on ebay for $20 but its made out of a hard plastic. Cant decide which to go with.

 

I've got the opposite problem.

Coolant tank was empty, drained oil, it was a milkshake and 3 quarts over filled.

Drained cooling system, coolant looked new but most of it was missing.

Time to pull the head....

 

Ouch, I was happy when the oil I drained came out clean, well dirty but not coolant contaminated.

The more I think about this the more confused I get. When I pressure tested the cooling system at 13-14psi it did not drop for the hour it was pressurized. Wouldn't it have dropped if it blew an oil cooler seal?

 

Just did a compression test, basically the same as the last time I did one. Going to service the oil cooler and see what happens...

 

Me too Paul. Ordered the seals and alignment tool last night. Hope this fixes the problem and its not something more serious.

 

Finally got around to installing the kit, seems to have corrected the problem but time will tell. Still cannot figure out how the seals could cause coolant to get into the oil, but not also oil in the coolant.

 

The pressure test blew a hole in the oil cooler on the water side. Then when the car was started, the oil pressure is greater than the water coolant pressure. The oil mixes with the coolant.

The oil pressure relief valve was closed and sealed the oil system, therefore no coolant in oil and the test showed no leakage, no pressure drop.

I would suggest pressure testing the oil cooler after removal.

 

really doubt that 13psi waterside would injure the oil cooler matrix meant to contain 100+psi of oil.

but if you need one i have 4 or 5 to choose from and can have tested.