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Had a mechanic change the valve cover gasket and front crank shaft seal and now have no oil pressure, 0. He had pressure for about 2 miles and then parked the car, returned, started it 0 pressure. Nothing leaking underneath.

Any thought on what they could have forgot to do or screwed up?

Crank bolt loose?

Must be. No other option....

I tried search but could not find any posts but I know I saw something on Intermittent oil pressure.

Does anyone know what can cause oil pressure to be fine sometimes on start up and other times it seems to take a bit of time to build.

You are basing this off what....your dash gauge? Could be your sending unit and not the pressure.

If you are, in fact, having an oil pressure issue (outside the gauge problem), you may have a cracked pickup tube. Has mostly occurred in race cars, but is a known weak point.

 

Jay

Bad gauge, oil filter not holding oil, oil pressure valve sticking, loose crankshaft bolt, cracked pickup tube. Could be a lot of different things, is there any particular circumstances when it happens? Like sitting for a few days, when the engine is hot/ cold,  etc.

The car had a valve cover seal replacement, and oil change, drove 3/4 mile 2-3 bars on oil gauge. Parked the car, returned couple hours later, car turned on oil light on, could hear lifters etc obviously no oil going into areas. Accelerated very slightly and it sounded ugly.

This may sound silly, but there is enough oil in it right? Could be a bad oil filter too, especially since it happened after the oil change

So mechanic never did seal because he realized it was to much for him to handle. Car is at Porsche now and they are scratching their heads as to why intermittent oil pressure problem. Any body ever have an intermittent oil pressure problem after an oil change, air lock?

bad sender?

 

p.s. - i merged the 2 threads on the same issue

At Porsche service, they are guessing at all kinds of stuff. I think its to coincidental that anything that wasn't touched, oil relief valve, sender, oil tube etc just happened to go bad right now. I think it has to do with something this useless mechanic did, oil change or valve cover gasket. 

do not make that assumption.  far too often people assume that something has to do with something else, or they rule out a new part just because it is new.  things fail.  new parts fail.  timing almost never has anything to do with it.  the rule in diagnostics is to not apply post hoc ergo propter hoc, but instead use occam's razor.

 

bypass the sender and check the pressure with a guage.  those senders fail all the time, with no warning.  i have personally replaced 4 of them. 

I have never had this problem on my other 968's but this one a 92 very early model has me worried as the oil pressure gauge just started moving. It goes down as low as betwwen 1-2 when I stop at light but as soon as touch the gas it goes right up to 5. I don't know if it is ok to drive to mechanic or I should have it towed? Any body had this problem and still able to drive the car? thank you in advance :glare:  :whine:

Is this with engine at operating temp? Owner's manual says when warmed up, oil pressure gauge can drop to 0.5 at idle and should be approx 4 at 5K rpm. 

 

Oil weight and level? 

thank you for response, the car is warmed up for sure. I didn't look at owners manual but I never notice this gauge going up and down like this. Oil level is right on full and it is 10-30 oil I live in north east very cold now. Not sure if that matters. I am just worried that if I drive it I may cause more problems? When driving the oil is on 5 and stays there, but when I stop at light it drops. 

2-2.5 at idle is correct 4-5 at 2000 rpm is correct


What does your owners manual say about viscosity in you locations temp range


I run my car on 20W50 as thats what the manual says, and I live in the UK

 

I have to check don't know off hand but I don't think it is 20 50

Before you do anything, use a mechanical gauge to validate your information.