Sorry guys I realise from researching this its been covered a lot, but I've been monitoring the oil pressure situation with my own car and would like to get the thoughts of those in the know as I haven't found any views directly relating to the data my car is providing.

To start its a 2000 manual convertible in standard tune bar axle back/intake, it has covered 85,000 miles.

It has fresh Mobil 1 5-30 oil and a new PF46E filter.

The below numbers are logged on a 23 degrees centigrade day.

From very initial cold start it will usually show 0 and then rise up to just over 40psi (on DIC & gauge) in a few seconds, I read somewhere that under high revs from cold it should be possible to peg the gauge, my mechanical sympathy has stopped me from doing this but certainly under acceleration from cold with at around 3,000rpm it'll go to mid 50's.

Once fully warmed up (oil temp of 212F and coolant 200F, using DIC & gauge) I'm seeing 24psi at idle, which increases to around 33psi at a 1500rpm cruise and rises to 45psi between 4-5000rpm, I've haven't got a reading revved out yet but it seems like it isn't going to increase much more.

The last bit of data i got was that if i leave the car for approx 1.5hrs, on restart it won't zero, the gauge will show about 20psi as soon as the engine catches and then build up to around 40 again.

The two common issues I've come across when looking into oil pressure issues have been failed oil pumps on cars making zero at idle (and not rising up) and oil pick up pipes too close to the sump preventing flow which appears to be diagnosed by oil pressure failing away quite quickly above 4000rpm and slow pressure build from cold.

If you can share any thoughts on my readings it would be appreciated. I don't have typical symptoms of the above issues but it would be good to know if I'm running relatively healthy figures for my mileage or if I should be considering preventative maintenance such as oil pump and pick up replacement. I'm in the UK so the other issue is I don't have another physical car to compare it too as these cars aren't massively common here!

 

I think you're fine within spec.

Here's a data point from me:
105k miles, 1999 C5. Heads/Cam/Intake full bolt ons NA build. I put a new Melling "High-Pressure" (Standard Volume) Oil Pump 15k miles ago.
With 5W-30, on a hot summer day (95F ambient temp or higher):
Oil temp = 100F; Oil Pressure = approx 40PSI at idle
Oil temp = 185F; Oil Pressure = approx. 28-30PSI at idle
Oil temp = 205F-212F; Oil Pressure = approx. 22-25PSI at idle
Oil temp = 220F-230F; Oil Pressure = approx. 19-20PSI at idle.

I might run back 10W-30 as I used to before, and if I recall I saw slightly higher PSI all across the board when running 10W-30. Then again, I don't see cold winters ever since I live in Florida so I can get away with running 10W-30 and not really affect much cold start wear.

 

My oil pressure starts at zero on very cold day or sitting for a long time... I think your oil pressure are normal...

here are GM minimum oil pressure.

 

Holy crap, those minimum oil pressures from GM are REALLY LOW!! I guess we have a good buffer then.

 

6psi at idle!! Surely that's ridiculous and you'd have serious engine issues by that point?

Thanks for the feedback on your own cars guys, makes me feel a little more comfortable! But Robmiz my oil pressure seems to always start at zero when the car is cold (left overnight or longer) regardless of in the summer or winter, what is yours starting at in warm weather? Has anyone got any info on what oil pressure you see at higher RPM's? would like to know if my 45psi at +4,000rpm is consistent with others.

 

My Data
99 C5 152K miles before replacing engine ( stocker was fine just replaced with custom built)
AMSOIL 0w-30 SIGNATURE SERIES
Hot Idle 210* 21-22 PSI
6000 RPM 48-50 PSI
As long as you have 15 PSI @ Hot Idle & 7-8 PSI per 1000 RPM WOT with a quality Synthetic at temp you are good on a SBE.
Just my .02

 

You might want try changing the oil filter or different brand, if you’re getting zero oil pressure more than a few seconds. PH46E has anti drain back valve.

 

It's normal for the gauge to take a second to move away from zero after a start. The instrument cluster doesn't "come alive" until after the engine is started again after cranking. Also the instrument panel oil pressure gauge is very "laggy" in comparison to actual reading..its' very much damped to keep it smooth moving.

If you're really worried about oil pressure after the car has sat a long time you can fully depress the gas pedal while cranking which will disable the fuel injectors-- you can crank and build pressure before any fuel is introduced. On my car though, after sitting a couple days, it takes like 10 seconds of cranking to see any oil pressure though. This won't register on the instrument panel as it's not active during cranking, but you can see real time oil pressure with a scan gauge or aeroforce gauge etc.

 

[QUOTE=328isport;1601730886]6psi at idle!! Surely that's ridiculous and you'd have serious engine issues by that point?

There is no load on the engine at idle so 6psi is fine