xsboost90

I run only 20w50 Castrol in my car and i never see the temps get above the mid way point on the gauge. Im sure if you run a lower weight oil or the car gets hotter, you'd see less pressure- i do prob get to about 2.5 when hot actually, but 1bar is crazy low i would say.

J Berk

I was concerned about it prior to the start of the last track season....but I did some reading (including Clark's) and spoke with my mechanic who club-races a 951 and daily drives an S2.

He was not concerned and knows my car. I am also suspect of the oil pressure sensor...and will probably change it just in case.

Going to continue to watch it but not 'worried' like I had been.....

Oh and I use 20W50 Valvoline racing oil l...but my car will get quite hot particularly at mid-summer events....never in the overheating range but hot.

pjburges

So, if V2 is correct about these things being topped off to get good pressure, what would happen if not all the oil pumped up into the engine goes back to the pan.... This is the 16V head and like a 968 - doesnt it have a check valve up there in the head? And couldnt you fill that head to the top with oil, thereby lowering the oil level in the pan? Im stretching here!

Today Im going to machine a bung for a manual gauge. Having driven the car this morning though, the oil pressure gets gradually poorer as I drive. It gets pretty low within 5 minutes. HOWEVER, if I shut the engine off, wait 60-120 seconds and crank back up, pressure is pretty decent again, however still low at idle (~1 bar according to the gauge). And its 33 degrees today and Im definitely not driving it hard! 5 more minutes of driving and we are back to achieving the poor 2.5 bar pressure on the gauge MAX. Any more ideas? Could it be that check valve?

J Berk

~1 bar @ 5mins after the car is started when it's 33 degrees out would make me very concerned....

I would definately not drive it until you get to the bottom of the problem.

have you searched here on the 944 forum under "CRACKED OIL PICKUP TUBE" ?

From what I've read here it's another common issue.

Tom M'Guinn

If the low pressure is confirmed with the mechanical gauge, then I'd work in the order of convenience:

1. Confirm front pulley bolt is torqued to 150+ ft lbs.
2. Try Maxlife 20/50 with a Mahle or Porsche filter
3. Reinstall the OPRV with an alignment tool
4. Pull pick up tube and check for cracks and replace its seal and those rod bearings (did you re-use the old seal when you checked the rod bearings?)
5. Try a different oil pump

pjburges

A little update on this. Ive been driving my chevy while I find the free time to work on the Porsche!

Low oil pressure is confirmed with a mechanical gauge. The electrical unit was dead on.
The oil is 20W50 VR1 with a black Porsche filter
The crank pulley bolt is torqued to 150 ft lbs

I removed the OPRV and some small black rubber chunkies were on the outside of the valve. Looked like a munched black oring or leftover seal material? It could be anything, but it was soft. Also, the green o-ring at the tip of the valve looks pretty beat up. I just replaced that o-ring 1000 miles ago. I can thread the valve most of the way in by hand - then it gets tight. The green o-ring instead of being round, has a concave surface on the sealing side of the o-ring. Its hard to describe. Just imagine round on the bottom where it seals against the OPRV, concave on the top where it seals against the housing/ block. Odd micro-tearing patterns in the polymer across that concave area...

Another symptom I've just noticed is that as I start the car pressure is a little slow to build. Even more curious is that for a fraction of a second it pops to 4~5 bar and then pops back to 3 bar. 3 is all it will hold regardless of RPM, and idle is about 1bar. The mechanical gauge doesnt see this brief little pop of pressure at idle, but the electric one does. (very brief climb and release)

Any thoughts? What alignment tool and seals / o-rings do I need to rebuild and align the 87+ OPRV?

pjburges

Also - I replaced the seal for the oil pickup when I had the pan off looking at the bearings. I didnt see any cracks in the oil pickup at that time, but I've been on a streak of bad luck....

F18Rep

Side note/question. I did this too, I think. I took a fitting (18mm plug - IIRCC) and drilled/tapped it to 1/4npt. Kind of a pain, did you come up with a better way? Bruce

944Ross

This sounds like an OPRV malfunction, if it's real (not a gauge glitch). Are you saying that when you start it, it runs up to 5, then snaps down to 3? Or while it's idling, it periodically jumps up to 5?

pjburges

F18 - I have an old lathe in my garage and thats exactly what I did. I removed the plug underneath the oil filter (90*) off the sending unit bung and held it with a collet in the lathe, center drilled, drilled and tapped for 1/8 npt.

944Ross- Yeah the low pressure is confirmed with the mechanical gauge - when I first start it up for a split instant it snaps to 5 bar and back to three. After that it will never do it again. The best I can get is 3 bar.

pjburges

BUMP

Ok new OPRV valve and o-ring and it eats the oring down in less than a few minutes of running. Also, I remove the OPRV and crank the car, no oil comes flying out the hole - is this normal?

austin944

I can't help you much, but I found a few threads dealing with that question:

https://rennlist.com/forums/5605834-post13.html
https://rennlist.com/forums/944-turb...-question.html
https://rennlist.com/forums/944-turb...-symptoms.html

Clark's Garage has a decent write-up on the OPRV and the oil cooler seal replacement. I followed those instructions when I did mine on my '84 (three-piece valve).

L8_apex

PJ - I posted a reply to your later thread, then saw this. Already tried a NEW OPRV? That makes my other reply a moot point.

When the OPRV is not in place I would think that a lot of oil would spray out.

Could there be debris or an obstruction lodged right at the point where the tip of the OPRV seals in the housing? That could explain both the chewing of the o-ring and the blocked oil flow out the OPRV hole. (But not necessarily the low oil pressure!)

dally_de

i have some identical problem...about a month ago my pulley for steering-rack was bad (the one on the crankshaft)...so now i have replace it and after starting the car i got 1-2bar on the oil gauge and also light come on... before that i had good oil pressure...i can't understand if this has something to do with the changed pulley ????
could the main bolt that keep all the pulleys in place be the problem???please help

joonas

One post about valves.
https://rennlist.com/forums/1812944-post27.html

Do you have the right O rings?

Does your OPRV look like that