Low Oil Pressure

[Drago]

This evening on the way home from work my oil pressure gauge dropped far enough (about 1.5) for the warning light to come on. The gauge also rises and falls with the engine RPM, which is something that I've not noticed before (though not unexpected to a certain extend I guess).

What I'm looking for is some guide lines as to what the gauge should be reading during normal operation of the car (cold, hot, high RPM, low RPM)? Also, does anyone else's fall as far as 1.5 and if so, does the warning light come on?

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1986 944 NA

[1.2gees]

According to Porsche, it's OK for the pressure to drop to 1 bar, and the light to flicker at idle if the car has been running hot, or has been driven hard.

Oil pressure fluctuating with rpm change, is normal.

I'd switch to a thicker oil, and it sounds like your engine is a bit tired, but it's probably not worth it to do anything about that, until a rebuild is necessary.
Ahmet

[Weldin]

BTW - Whats the psi conversion to bar? DOes 8psi per 1 bar sound right? Or is it 16 psi per 1 bar? ive seen it a couple of times but forgot!

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[1.2gees]

1 bar is 14.5038psi.
Ahmet

[asidrave]

Ahmet, that is a precise calculation. sometimes my oil gauge needle jumps, is that normal?

[1.2gees]

I've seen many 944s, that have the same problem, jumpy oil pressure gauge. It's not normal, but definitely common. Usually the pressure sender is the culprit. I wouldn't really worry about it however, unless it bothers you.

PS: It's normal for the gauge to shoot up, when rpms first start to increase above idle. Again according to Porsche, 4 bar is good system pressure at 5k rpm, most our cars do better than that though.
Ahmet

[Drago]

After checking my owners manual I at least feel better about the low pressure but still....the light doesn't just flicker, it's on completely and doesn't go off until the gauge reads 1.5 bar.

[Drago]

BTW, the car has 121K on it, no rebuild, and has 170 psi +/- 3 psi across the bores.

Also, I may have been driving it a little hard

I was unable to reproduce the problem this morning.

Thanks for the info.

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1986 944 NA

[Mrmerlin]

[QUOTE]Originally posted by Drago:

Hi Drago , before replacing anything I would change the oil I use Mobil 1 20 W 50 synthetic, but a great 2nd choice would be Valvoline 20 w 50, also replace the oil filter..... then start checking for a bad sending unit..... there are 2 wires on it one is for the red lite and one is for the gauge.....Stan