Oil pressure system

[philippeF]

Hello
My 944s2 takes a few seconds to build oil pressure ....
Then, everything works fine
3>5b all conditions
Any idea to prevent something ?
Kind regards
Philippe

[Leo944]

I had a similar experience with my 944 that got progressively worse to the point of not having any oil pressure at all.

I replaced the OPRV (oil pressure relief valve) and the problem seems to have been resolved.

Here are a few threads that might help you diagnose your problem:

86 944base No Oil Pressure, OPRV, Relief Valve O-rings assembly

No oil pressure on cold start

Leo

[v2rocket_aka944]

Is your oil level full? ~6.3 L I believe.

What oil filter do you use? Only the Porsche/Mann filters have a built in "anti-drain valve" that will help build oil pressure faster after the car has been sitting and not run. Other brands will let the oil drain backwards into the sump so no oil ready to move when the car first starts.

If you don't drive the car often, a trick I like to use is removing the wire from the ignition coil to the distributor cap, and then cranking the engine with the starter for a few seconds until oil pressure appears on the gauge. Then re-connect the distributor wire and start the car.

[philippeF]

Thanks
Yes filter is from factory, i've heard about 2 oprv different parts ?
One tool needed too ?
Philippe

[dgcantrell]

To replace the OPRV, unless you remove the oil cooler housing from the block, you do not need the alignment tool since you would be simply removing and replacing just the OPRV.

[philippeF]

Thanks
I'll do this way ... What about the pressure valve on the head ?
Regards
Philippe

[dgcantrell]

I'd concentrate on the primary down on the block because it is about 2" away in the oil passages from the pressure sending unit. But before you replace the OPRV, remove and clean the sensor. There is a small hole in the end that can get gunked up and could result in erroneous readings. Remove it and let it drain. Then use some carb or brake cleaner spray to help clean out any crud in the hole. Put it back in and see if the readings change.

[philippeF]

I've no reading error or problems, but it takes about 3 sec to get full pressure on start, (when I let the car a few days) here's the question ....

[dgcantrell]

Hmm... Does it jump up any at all on those first 3 seconds? To like 1 or 2 bars? 2 bars is 28PSI which isn't bad.

I mean, when you crank it up and it fires, the oil PSI jumps immediately to 1 to 3 bars and then after 3 or 4 seconds pegs at 5? Or. Does it stay at 0 and jump straight to 5 bars after those 3 or 4 seconds?

[philippeF]

Hello
From 0 to 5 bars gradually ...
Car runs fine otherwise ... 3 bars at idle, even very hot

[dgcantrell]

Still sounds like a drain back issue. It could very well be the o-rings on the OPRV allowing the oil to drain back. The o-rings can be had cheap from here at Pelican and are replaceable. Get 2 sets in case you bugger one getting the OPRV back together.

[philippeF]

Thanks
I'll buy them from Porsche.

[JonA]

If this is a one piece valve I do not believe you should disassemble it, based on my experience. Clean it and inspect with the valve together, replace the o-ring on the tip and put back in the engine. Disassembly serves no purpose and causes nothing but heartache.

Jon

[dgcantrell]

I just did mine and had no issues other than the plastic alignment tool I bought was undersized. It's really not a one-piece valve. It's more like 6 pieces including the o-rings. Lubing the parts as they go together was all I did. The o-ring that fits into the outside piece is the tricky part. Some recommend putting it in the outer piece first and slipping the inner piece into it. I put the o-ring in the groove in the inner piece, greased everything up good and gently slipped it into the outer piece, giving it a slight twist as it pressed in.

[philippeF]

I drove today, really smooth engine, no noise, still 3 sec to build pressure ... I will need 2 Orings according to the PET, right ?
Philippe

[dgcantrell]

Yes and they are the same. Get three just in case you have difficulty getting the thing together and bugger one..

[Leo944]

Philippe, I don't know the model year of your car and you could have two types of OPVR. If you have the new type DO NOT take apart just replace the outer o-ring, part # depending on the model year.

I had huge problems because I took it apart and could never put it together again. Read my prior thread: 86 944base No Oil Pressure, OPRV, Relief Valve O-rings assembly

Here are the early and new designs:

If you have the old type (3 separate pieces - spring) then I suggest you purchase the retrofit new style either used & purchase a new o-ring for it or a brand new valve.

If you already have the new style just purchase a new o-ring. All the part numbers are shown here:



Good luck!

Leo

[Leo944]

The outer o-ring is the one colored green. That's the one that you should replace.

[philippeF]

Thanks Leo944

Why shouldn't I take it apart ? a spring inside ?
regards
Philippe

[dgcantrell]

There is a spring inside but taking it apart buggers the internal o-ring. Some people have a difficult time getting it back together correctly. I had no problems getting ming back together. But replacing the o-ring on the end is a snap and is probably is what is causing the drain back issue. Shouldn't take 15 minutes, in and out. 24mm (15/16") socket fits it. Yours will be the later on-piece affair being and S2.