Replaced psi relief valve, still blows filter gasket. What next?

 

You've got some debris or blockage plugging the oil galley after the oil filter. Any major work been done lately.

 

Have you check the PCV. If the crackcase is getting pressurized that will blow seals.

 

That will generally blow a crank case seal... not an oil filter seal.

 

I had a separated OPRV and my filter gasket would blow. The way I understand it if the OPRV is not working properly the next weakest point in the system is designed to be the filter gasket as not to harm anything important. However, that doesn't happen much unless there has been bad work done.

So like Steve said, any major work?

 

In the '88 there are 2 green "O" ring/seal on the one piece OPRV. One is ont the bottom and the other is internal. You may have a bad internal "O" ring. The other thing is that the bottom "O" ring may have come off while removing the OPRV and is in the oil path. It could be at the bottom of the OPRV hole.

Porst 4 in the link has the TSB to replace the inner "O" ring on the OPRV.
http://forums.pelicanparts.com/showt...highlight=oprv

GL
John_AZ
1988 924S + 1987 924S

 

Only engine work done lately, replace vacuum hoses, 8 months ago. Engine oil always clean when changed (honey color). Is there a psi control valve in the head? I have heard of this but cannot find it in the Haynes manual. PVC is clean.

 

There are 2 oil pressure senders one right by the OPRV and I can't seem to remember where the other one is...

 

I think the oil drainback valve in the head started on 1989 8 valve cars. 16V had them starting in 1987.

 

And I had a clogged anti-drainback valve clogged in my 16V and all it did was keep oil from getting up to the cams, it didn't blow out the oil filter seal.

 

Every 944 I've owned including the 83 has a check valve in the head. Follow the flow and you'll see it almost has to be a blockage at or just after the oil filter or a stuck OPRV as suggested. I don't think the OPRV can shunt the full oil flow if there is a large downstream blockage. I'm surprised his cooler seals didn't blow out also. I still can't see how a stuck OPRV can raise pressure to downstream components based on that flow chart since I don't think it's supposed to function as a regulator, just a relief valve.

Oil Flow Chart

 

So I just noticed this, you said you you replaced the OPRV? With a new one or did you just reseal the old one?

 

Good info to check on. Cooler seals did blow. Rebuilt cooler with a new Kit. I'm feeling I have a blockage or the check valve may be stuck????

 

When my cooler got replaced right before I bought the car, the mechanic did not line up the housing correctly, which causes alot of stress on the OPRV and at the very least keeps it from operating correctly.

You should remove the OPRV (which is not much trouble) to check the O-rings and make sure its moves in and out of its housing easily. If it doesn't, borrow or buy the tool for lining up the housing and get that fixed.

 

+1^

You need the late OPRV alignment tool.

GL
John_AZ