951 no oil pressure
#1
951 no oil pressure
I know this is an old can of worms reopening, but after examining almost all posts of the kind, over and over, I could not find a feel good resolution... I ran the car hard for few traffic lights, after I came to a low speed creep to look for parking on the street I noticed the " ! " and low oil pressure lights came on, and the oil pressure dropped to 2 bar at 3k and when stopped, dropped to 1 bar! No metallic noises or weird vibrations engine was smooth. I parked and left it to cool off, the next morning I started it and no ticking no ratleing noises, all sounds and vibrations were good, but oil pressure was low at 2 bar and all the above mentioned lights were on, after warm up pressure down to 1 bar, after couple of light revs pressure flickered to 5 bar and then back to 1 but then flickered more and drops to "0", and brake lining and brake system lights come on! Now engine is smooth and normal sounding except all the above. WTF? I have less than a bar of pressure at the instrument cluster gauge, no metal noises, I checked cluster is good, wiring at sensor is good cranck bolt is in the proces of being checked but the pulleys are straight on and when removed the filter it's full of oil so its priming ok and pump gear must be straight on! I noticed when engine is running I pull the dipstick and oil actually becomes higher than the top mark??? Other wise oil is at just above top notch. And again engine is running smooth and quite with instant trotle response. Any input will be apreciated...
#5
it's either a small problem or a big problem
small problem: your oil pressure sender or sender signal wiring or sender ground wiring broke.
big problem: rod bearings or oil pickup tube cracked.
i'd start with diagnosing the sender electricals.
small problem: your oil pressure sender or sender signal wiring or sender ground wiring broke.
big problem: rod bearings or oil pickup tube cracked.
i'd start with diagnosing the sender electricals.
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#8
while I would agree to hope for electrical, my gut feel is that it would be a work/doesnt work situation, vs a low oil pressure.
you could do some easy thing, change the oil/filter, check for any blockage. Otherwise, your looking at some decent engine work to get at the oil pump/pickup tube.
you could do some easy thing, change the oil/filter, check for any blockage. Otherwise, your looking at some decent engine work to get at the oil pump/pickup tube.
#9
Filter has couple hundred miles on it, and its original porsche.., now I don't question the idea but is it, if the valve in the filter is stuck open no oil pressure and if stuck closed, it is high oil pressure???
#10
It would be good to verify the low oil pressure condition with a mechanical gauge. Installing one will require you to get an adapter that goes between the oil thermostat housing and oil filter.
I doubt the problem is in the wiring. A break in the circuit, will cause the gauge to peg at 5+ bar. The warning light and gauge are driven by separate wires (sending unit controls gauge reading and warning light separately). So, if both the gauge is reading low and the warning light is on, the sending unit is relaying a low oil pressure condition. This can be due to the oil pressure actually being low, or the sending unit's pressure sensor has failed.
I doubt the problem is in the wiring. A break in the circuit, will cause the gauge to peg at 5+ bar. The warning light and gauge are driven by separate wires (sending unit controls gauge reading and warning light separately). So, if both the gauge is reading low and the warning light is on, the sending unit is relaying a low oil pressure condition. This can be due to the oil pressure actually being low, or the sending unit's pressure sensor has failed.
#11
If the OPR is stuck open you would have low oil pressure, because a large volume of the oil will be directed back into the pan, without going through the bearings.
The filter valve being suck open will not hurt oil pressure. But it will cause the oil to not be properly filtered.
If the OPR was stuck closed, you would see very high oil pressure. This, sometimes, will cause the oil filter housing to rupture.
#12
I would definitely confirm if you have low oil pressure with a mechanical gauge before driving the car again. These cars do not respond well to low oil. my gauge was pegged and I spent a day debugging the wiring just because I wanted to be sure my pressure was ok.
#13
could be grounds, if the other lights are coming on. mine reads 3-3.5 bar at idle and 5bar at around 2000rpm and up, but sometimes with the headlights and foglights on even driving around (~3000rpm) it will only read 3 bar. grounds need to be checked...
#14
WOW "fortysixandtwo"... This is great input, thanks!!! I m heading for the store to get the gauge, it should be a spin-on adapter right?
So it is a possibility of bad filter, OPRV, OP-Sending Unit... if its light situation !?
So it is a possibility of bad filter, OPRV, OP-Sending Unit... if its light situation !?