Hectoy

Hi all, new to the forum thing but I've found so much useful info that I joined to ask a burning question about "low oil at warm idle", I tried most all remedies for my issue, from replacing the "oil pressure relief valve and spring", changing from M1 0w40 to Motul 5w40 to M15w50, and still after getting off freeway after a 20 minute ride to work at about 50 some degrees the oil pressure needle rest between .5 bar and 1.
I also thought that my cooling system might be causing this cause the oil is cooled by the coolant in the exchanger, so, and thats a big so, I replaced coolant tank, water pump, and installed a low temp T-stat, with new G40 coolant (pink). so there it is in a nut shell.
I don't have any clicking, tapping, vibrating noises of any kind, engine never sound so good, and it does have 120 k mile on the original engine
and I can still hit the 140 mph mark she is smooth as ice.
Only thing I could think of is the spring in the "oil relief " is exactly the same as the one I took out, and I can't find info on the size of the updated version spring to compare to.

thanx all

Hectoy

Quadcammer

have you considered the sender may be inaccurate? Have you compared to a mechanical gauge?

Joehatz

GM vehicles have this problem.
The oil pressure will go to zero and the warnings to stop engine will come on.
The fix is first change oil and filter and if this does not work replace sender unit.
I have had this happen on 5 or 6 vehicles.
Have a Mechanic put a master oil pressure gauge on when car is warm and see what it reads.
If you have good pressure the change the sender.

Hectoy

Back when I noticed my oil pressure needle bouncing around it was forwards the end of summer 2017 when we had those temps up in the 114's , thought it was just extreme heat in slow traffic, but it didn't change much even on cool days thats when I found one of the posts about the pressure sending device, changed it and the oil with fresh 0w40 and not much change and did more resarching and somewhere was mentioned the AOS, changed it, still nothing, then everyhing I did in the previous post, now I hear some say the scavenger pump might have a simular symptoms...

swingwing

You are not reading physical oil pressure at the instrument panel. It's an electrical signal from the oil pressure sensor on the engine. If you think you have low pressure you must verify with a mechanical gauge. Otherwise you're just guessing.

Hectoy

Your absolutely right, it' very simular to the water temp gauge, it says it' 175 degrees but my OBD II shows temps to swing from 168 all the way up to around to 200 range pending driving style of the day.
I found a port I ientical to where the oil pressure sending device sits, it on the opposite side, I thing if the engine was a turbo it would have 2 oil sending units. I checked the oil circuits and found that oil is present at that point, only thing is that it' pretty close to the coolant tank and might be to difficult to setup a mechanical oil pressure guage.

Hectoy

not sure if I did it right ( attaching pic's), here are 2 pic's, right side of my engine (simular) showing "oil sending device" . And the second showing the left side where a second "oil sending device" would be if the car was a factory turbo, this is where is had planned to put the mechanical gauge.

PTEC

The second picture is just showing where they plug off the oil pressure sender hole. They use the same casting for both bank cam covers and you only need one sensor so one side gets a plug. The 997 turbo of this generation used a completely different engine. Plugging a mechanical oil pressure gauge into that port will do the trick nicely.

Hectoy

Great I'll figure out how to attach a oil hose and mount an actual high temp/ high pressure hose with a mechanical gauge so I could see it, thanx for the big boost of confidence...
Hectoy