I recently noticed that when my car idles, the oil pressure indicates pressure lower than '2' on the guage. Also when I first start the car it takes a while for the oil pressure to build. However, upon a gentle tap of throttle leading to an increase in RPM to 2500 and above the oil pressure guage indicates its maximum value. Is this normal for a 1986 Turbo?

Thanks you for your feedback.

 

How long is "a while"? If its only a couple of seconds I'd say you don't have much of a problem. The low pressure at idle is normal if the engine is warm.

 

Generally, when it idles oil pressure ALWAYS run low (below '2'), only at higher RPM (2500 and above) does it reach its maximum value

 

Which oil grade are you running?

I get 1.5~2 bar oil pressure with a/c and some hard driving. I run on 0W~40 oil (REALLY REALLY thin).

I used to get 2.5~3bar on idle using 15w~50.

Anyway, anything over 1,800~2,200rpm you should be reading 4bar+.

Again, check the grade of oil (oil weight) because it REALLY effects your oil pressure, as well if it is synthetic or normal.

 

I got worried after oil change when mine went down to 3 bar at hot! It never used to go below 4bar. Checked it out with a wet guage and it is reading correctly! Concern over nothing it seems!

 

Yeah, I have noticed much lower oil pressures with M1 15w-50 than with Chevron 10w-40 conventional oil. This is especially the case when the ambient temp is high. My 2k+ rpm pressure actually drops a hair below 5 bar with the Mobil 1 15w-50....hmmmm...it didn't happen with the cheapo Chevron oil.

Max

 

Syntheitcs ALWAYS read lower oil pressures

 

Interesting, my 951 with Mobil 1 15-50 does just the opposite compared to dino: 5 bar@cruise; never less than 3 bar at idle even after a hard run. Most M1 users say the same but other folks have complained about high temp viscosity breakdown. I'll see what happens after it's been in there for 3K.

Steve

 

I am pretty sure this isn't true. What other synthetics have you tried? Do you have reasoning to back this up?

I think M758 switched to Amsoil racing synthetic and he says he sees much better oil pressures than with M1 or any conventionals.

Max

 

Surely high oil pressure is not the be all and end all. Whats important is the quantity of oil thats is getting round the engine.
As the oil heats and gets "thinner" less viscous then it takes less pressure to pump the same volume of oil.

Runnig with 0-40 is not bad for the engine in terms of wear, just means that you might loose more thought the seals than a "thicker" oil.

 

could be sludge in the sending unit lines as well that is dampening your readings

 

How can I clean out this line?

Max

 

remove the sending unit and spray out the inside with some carb cleaner