peter y.s pang

My 993 Tip running smooth. but recently i notice that, cold start the pressure gauage show 4.5 bar and running for the few min, when car idle , the oil pressure gauage will be 1.5 - 2 bar. if the car running real hot ( temp gauage point 9 - 10 o'clok) , car idle will be only 0.5 - 1 bar only. Is it due to bad oil pressure senor ? thank for hlep

deekay911

Oil pressure will always appear lower when the oil is hot. 1 on the scale shouldn't worry you.

techman1

Add in age. I seem to notice the hot pressure will slowly drop as the oil ages.

Vandit

Tell us what oil and weight you run. Auto or manual?

ca993twin

the old "rule of thumb" that I grew up with is (with hot oil): you should have a minimum of 10 psi of pressure per 1000 RPMs. Since our gauges read in BAR, not PSI, and 1 BAR is ~14.6 psi, you should have roughly .7 BAR at 800 RPM idle. You are fine.

peter y.s pang

is there any method to turn up the oil pressure into 1 bar even the car in hot engine idle. my car only get 0.5 bar when engine hot in idle with 600 rpm . currently just renew the engine oil with motul 15W-50 engine oil.

pp000830

Hi Peter,
The gauge is telling you all the correct stuff. When cold the oil is more viscus and so the oil pressure is higher, when warm it is less viscus and so it is lower. I suspect the gauge in the dash is not the most accurate. Seeing that the 50 weight oil you are using is at the high end of the viscosity range (thicker) and you are not experiencing oil starvation sounds like noisy valves I bet the low reading is telling you more about the gauge than the absolute oil pressure. If you have a concern just take you car to a shop where they have a calibrated gauge to check your oil pressure or some other test to validate adequate lubrication.

Hope this helps,
Andy

Quadcammer

well, at what oil temperature is the oil pressure that low?

peter y.s pang

the oil temperature point 10 o'clock, at that time, the oil pressure only show 0.5 bar. but once the oil cooler fan start in high speed. the oil temperature drop to 9 o'clock. the oil pressure raise to 1 bar.
Even the cold start the oil pressure only get 4 bar.

Quadcammer

well your first goal should be to keep the temp from getting that high. 10 on the gauge shouldn't happen unless you are pushing very hard or stuck in traffic in high ambient.

Johnny_law

Is it possible that the OP's low speed fan resistor has failed? And that is accounting for the perceived loss in pressure.

peter y.s pang

The low speed fan work fine, it start when oil temperature just pass 9 o'clock. Is it posible tunning the idle speed at 700 - 750 rpm and how ? i thinking, the low oil pressure due to the idle speed too low. as currently my car idle only got 600 rpm. seems toolow.