OPRV and OPSU

[jamesjedi]

I have an 86 NA. My car is running very rough with high oil pressure. How can I check the OPRV and the OPSU? I have searched and not found an answer.

I do not think that it is the OPSU that is causing the problem because the oil pressure was strong enough to push my dipstick out. Also, there is no reading with the key in and the engine not running. I would like to rule out OPRV, how do I check it?

Thanks

[John_AZ]

You have a '86 944 (please update your signature line)

You should have the late OPRV-----just to be sure, compare it the the pictures in the tech article below.

There is no way to "test" an OPRV. If you feel it is giving the wrong reading, you should replace the "O" rings. These usually decay and cause problems. Clean the OPRV parts.

Get a new aluminum crush washer or the OPRV will drip when installed.

To rebuild-----see post #4
Using SeaFoam Product

To see which OPRV you have:
http://www.944online.com/pdf/oilcoolertech.pdf

Pelican has the "O" rings.

GL
John

[wild man]

I don't think it's possible for oil pressure to be high enough to push out the dipstick. Most likely either a blocked air/oil separator, or excessive blow-by.

Is your pressure gauge pegging out at over 5bar when warm?

[jamesjedi]

At first I thought it might be blow-by. The oil pressure is now coming down after it is warm. To about 3.8 at idle. It is pegged at 5+ until the engine has completely warmed up. It is still running rough at idle. At higher RPM's the engie sounds good.

How can the air/oil separator be checked? I also want to take out the OPRV to inspect and reinstall. Do they simply "bolt back in" , or do they have to be aligned?

[Rasta Monsta]

If you don't disturb the oil cooler housing, you should be able to R&R the OPRV without realignment.

[John_AZ]

Rasta is correct.
Clarks says to replace the crush washer and the "O" rings if you remove.
Found at bottom of page.
Oil Pressure Relief Valve General Information

GL
John

[wild man]

It's been quite a few years since I've been into one, but after you unscrew the retainer plug, you should find the spring, and the the moving part of the valve behind it. If my recollection is correct, there is an O ring on it, which might be getting stuck. You may want to try to clear out blockage in the AOS by pushing compressed air through it in reverse direction, with the filler cap removed.

What weight of oil are you using up there?

[jamesjedi]

Do you mean blowing air into the oil fill hose?

[wild man]

No. I mean blowing air into the hose that feeds from the unit into the air intake boot, near the throttle body. But make sure that you have the oil filler cap off, and probably also the dipstick out, to prevent pressure buildup.

[jamesjedi]

I will try it. Everyone, thanks for help. I will post the results.

[jamesjedi]

Well....I got a chance to look at the car today. Before I did any of the recommended steps to reduce oil pressure, I looked at two spark plugs. One was wet, the other was a little oily. Also, had a look at the oil refill cap, it has a a small amount of coffee cream. I now know that coolant is getting into the oil.

If I do a leak-down test, will it give me an accurate read if the head gasket is blown? Or, is the head gasket issue due to the high oil pressure? Either way I will have to deal with the head gasket. Not sure what to do next.

I want to determine if there are other engine problems.

[massive]

Check out my blog 944 Foot To The Floor: How to remove and replace OPRV (Oil Pressure Release Valve) on a Porsche 944 you might find some useful info about the OPRV there.

[John_AZ]

Originally Posted by massive

Check out my blog 944 Foot To The Floor: How to remove and replace OPRV (Oil Pressure Release Valve) on a Porsche 944 you might find some useful info about the OPRV there.

Dave, aka massive.

Great pictures and write up. I will use your information and link to help others.

I do have a problem with your final comment and information from the Porsche mechanic. See pic.



Do not use the OPRV as an alignment tool if the housing comes off.

Your Porsche mechanic has years of knowledge and the "feel" needed to prevent an OPRV from binding. Members doing the OPRV housing for the first time, do not have this "feel" for a binding OPRV. The alignment tools are required for this procedure for a novice mechanic.

I was unable to comment on your web page.

But, again excellent pictures and writeup.

John

[massive]

Cheers for the praise, yes totally agree you do need a bit of a feel for these things sometimes. I would say though that removing the oil cooler is beyond the scope of most novice and indeed even some amateur mechanics. But if you have reasonable common sense you should be able to perform the realignment using the OPRV, just making sure the oil cooler doesn't slip whilst you're tightening up the mounting bolts.

Originally Posted by John_AZ

Dave, aka massive.

Great pictures and write up. I will use your information and link to help others.

I do have a problem with your final comment and information from the Porsche mechanic. See pic.



Do not use the OPRV as an alignment tool if the housing comes off.

Your Porsche mechanic has years of knowledge and the "feel" needed to prevent an OPRV from binding. Members doing the OPRV housing for the first time, do not have this "feel" for a binding OPRV. The alignment tools are required for this procedure for a novice mechanic.

I was unable to comment on your web page.

But, again excellent pictures and writeup.

John

[jamesjedi]

I have found that in my endless searches for information on this site, all to often there is no conclusion/solution to the problem. I appreciate the help and I will follow this thread through.

I plan on removing the OPRV for an inspection. Blow the AOS, then I will do a leak down test with the engine cold, as I do not want to run it any more. I just have to wait for the Longacre leak-down tester to arrive in the mail.

I hope to find the pistons and cylinders in good shape when the leak-down test is done. Thanks for any help that has been provided.

John, the pictures and write up are excellent.

James

[massive]

You can post a comment at the bottom of each write up

Originally Posted by John_AZ

I was unable to comment on your web page.

But, again excellent pictures and writeup.

John

[jamesjedi]

Could my problems be caused by a leaking oil cooler?

I will be doing the leak down test in a few hours.

[jamesjedi]

I have replaced the oil cooler seals. As I had the old style, I simply inserted it and tightened. I have also replaced the cylinder head. Engine is now running.

I went on a test drive and the dipstick has pushed itself out again. When i removed it while engine was running, I could see there is puffing coming from the tube. Any thoughts?


Thanks

James

[romad]

burn piston and or broken ring is possible. I have only seen combustion pressure blowing dipsticks

[Slam]

Time for a compression test, I think.