964-C2

I have been working on my 944 turbo S for a few weeks. Changing the oil cooler housing gasket, mounting an oil cooler in series with the stock one, new rod bearings, new oil pressure sensor, ++.

Well. When I am cranking the engine to get oil pressure before first start up, I have to crank for a very long time (30 + sekonds) before I see any oil pressure on the gauge. But when I get pressure, it goes to 5 + bars (just cranking). Same thing if I try 5 minutes later.

This is not normal, right? 5+ bar only by cranking?

Well, I tried this a couple of times, and when I go out of my car I see some oil under the car. My new mocal oil cooler has BLOWN (to high oil pressure) just by cranking?

What have I done wrong?

Thanks!

Jeff N.

I went through the exact same thing - it's about 99.9% sure you have binding oil pressure relief valve.

What year is your car? If you have an 86, there are two types of OPRV's available - which are you using? [edit] Right - turbo S. OK, you have the late model style of OPRV. You still need to align in some manner.

How did you align the oil cooler housing? Did you use the tool or align with the valve or forgo any alignment at all.

PS - did it look anything like this?

964-C2

I did not know I had to align anything....

Can anyone expalin please?

I hope I have not broken more than my new oil cooler...

Jeff N.

Search the archives..... ten gazillion posts on this. Search on OPRV alignment and see what you get.

Net is this - the OPRV bore is shared between cooler housing and the block. If you don't get the bore aligned, the valve binds. This is generally bad and you have a binding valve.

964-C2

Thanks Jeff!

Chris White

The turbo S has the one piece OPRV and its pretty hard to screw up the alignment.
5bar is possible with cold oil. With a stuck OPRV you can easily get over 150 psi….

I would guess that the Mocal leak is either a loose fitting or you applied too much torque and twisted/cracked the male fitting (I think it fails at a 2ft’lbs of force!). You absolutely have to have a good grip on the hex of the cooler fitting so that none of the tightening force is felt by the cooler body.

Once you have primed the pump (and that takes a while) it should get oil pressure quickly, if it takes 30 seconds every time that there is an air leak before the pump.

Grandpa#3

Hello, The OPRV has to be aligned properly to prevent any binding for correct operation and excess oil pressure. Did you install a new o-ring and crush washer on the OPRV? Look at the below link for explanation, old verses your new OPRV.

http://www.944online.com/pdf/oilcoolertech.pdf

Cheers,
Larry

Jeff N.

Chris did a better job of reading your post and shortlisting your issues than I did. Before re-aligning the OPRV, I'd follow his recommendations.

I did have an alignment problem that caused binding and excessive pressure with the one piece. When it was mis-aligned, I had to put pressure on the OPRV to get the threads to start. After I corrected the alignment, it took no pressure.

964-C2

The Mocal was twisted and "balloony", so I really think it blew because of to high pressure. The leak was in the middle of the cooler. No external damage.

As I wrote earlier, I did not know I was supposed to align the OPRV at all. I had had to use some pressure to get the OPRV in after I changed the oil cooler housing gasket (and fastened its bolts) the first time.


What I did after finding out I needed to align the OPRV was this:

I loosened the bolt on the OPRV and tried to take it out, but all that came out was the bolt and the spring (not the complete "one-piece" OPRV). I) When looking, I could clearely see that the remaining parts of the OPRV was not in the center of the hole of the housing.

To align the OPRV properly, I guess the best thing to do would be to take the housing completely off and put a new gasket on ++. But to do that I would have to take the x-over, sway bar ++ of again, right?
What I did was just loosening the 4 bolts that holds the housing and mooved the housing a bit to the side. By doing this the OPRV-hole in the housing was aligned with the remaining stuck parts of the OPRV. Then I thightened the 4 bolts again.

I was still not able to get the remaining OPRV parts out. I could feel with a screwdriver that it/they were "loose", but it would not come out. I think its new o-ring (which I changed the first time) was making it fit tightly and difficult to get out.
I put back the OPRV spring and bolt and tried to crank the car again. Oil pressure would not go over 2 bar this time (last time 5++ bar).

I have now started the engine, and everything looks ok.

Does this sound OK....? Do you think my OPRV is OK after what I just described?

Thanks!

Jeff N.

Re the health of your OPRV - hard to say. Personally, if it came apart in block and you never got all the parts out, I would be worried. Oil pressure is not something you really want to have any doubts about, eh?

What did you do with the Mocal setup? Remove it and plumb it back to stock?

You say you started the engine and everything looks OK? What exactly are you seeing? I'd be carefully watching the time to build while cranking, cold start pressure, hot run pressure.

Re if you decide to get back in there and go after it - I was able to get access to my housing by dropping the sway bar and pulling the belly pans. No need to pull the x-member. Loosing the oil lines was difficult, I was able to use a 32mm bicycle wrench with some success. I can also share it was a really miserable job; one I never have any interest in doing again.

Sorry to hear about the problems...