robmeister951

My 86 944NA that I've had for nearly 9 years now has started to develop a problem with oil pressure.

I have noticed on startup the oil pressure is getting slower and slower to build. It takes about 2 seconds now when cold overnight,
whereas a couple of years ago it was almost instant.

Is this a symptom of a cracked pickup tube?

I have the 3 piece OPRV. Oil pressure is good generally hot (~2.5 atm) or cold ~5atm
Oil cooler seals and the OPRV outer O-ring was replaced 12 months ago together with new HG and new valves due to
a dead cam belt tensioner.

Thanks for your help

Rob

njwilser

Two seconds does not sound that bad to me. Try a new oil filter. I believe I have had some issues recently and in the past w/ the anti-drainback valves in the Mahle filters. I bought an STP filter (manufactuured by Champion Labs / Porsche OEM) at Autozone and was going to swap it out w/ the Mahle but my symptoms disappeared again. Being that it is cold out, I am a little lazy, and there is moderately fresh oil in the car so I have yet to swap it.

Please swap the filter and report back. I am curious.
Thanks, Mike

KuHL 951

You said you replaced the OPRV outer O-ring. I assume you are talking about the metal sealing ring between the head of the OPRV and cooler housing? There is no O-ring on the 3-piece style valve. Again, 2 seconds isn't that unusual.

robmeister951

Mike,
Did the filter merry go round early last year, Mahle and Porsche Dealer supplied one (Made in USA), made no difference. Currently it's the Dealer one that is on the car. It seems to be getting worse as time goes.

Rob

robmeister951

Steve,

There are actually 2 rubber o-rings on OPRV, (see PET, illustration 104-1 9442 88 1 04 ) I replaced the one at the tip of the OPRV, the other one is hidden and requires dismantling the valve to get to it. Also the aluminum one you mentioned.

2 Seconds seems like a hell of a long time to me, no oil and engine is turning over at 1000rpm (33 times in 2 seconds). There is no load but something is wearing out!?

Cheers
Rob

robmeister951

Darn it I mean the ONE PIECE Valve. You are correct.



Rob

KuHL 951

True for the 1-piece OPRV but you said you had the early 3-piece style. All the 1-piece style has is a piston, spring, and cap. The piston itself is the engineered clearance piece. Even though it has a wide groove at the tip it is not for an O-ring. The grooved cavity helps keep the piston from drying out between start ups.

robmeister951

OK, I'm swapping out the original Porsche Dealer supplied filter with a Mahle. Will let you know how it goes.

Rob