Mark85Vett

Any ideas what GM considers "normal" operating oil pressure with oil hot and engine running under load at around 2000RPM in a 98 LS1??
Thanks in advance!!

Mark VerMurlen

Oil pressure will vary with oil temperature and engine speed. I would guess that you should have a pressure of somewhere around 40 psi under the conditions of hot oil and 2000 rpm. Now if the oil wasn't really hot, I'd expect more like 50 psi. I believe I've seen it mentioned that GM considers the minimum oil pressure to be 20 psi. That seems really low to me. I'd rather not see anything under 30 psi. What oil pressure are you seeing and what's the oil temperature?

- Mark

Jim 47

In addition, a higher viscosity oil like 10W-40 will give you a higher pressure than a lower viscosity oil like a 5W-30 at the same oil temperature and RPM. :D

Mark85Vett

It's my brother-in-laws car...he said that he sees around 40 in normal driving at highway speeds, but in the city, when the engine is turning, say 12-1400 RPM its in the 30's, and when idling, it's around 25. I consider that OK, but he's concerned about lower end issues at under 50,000 miles on the ticker...

vettenuts

A good rule of thumb is 10 psi/1000 RPM. If you are running Mobil-1, the 100 degree C viscosity is about the lowest of all the synthetics. Mobil-1 10W-30 is about the same. Try Amsoil or Redline (I prefer Amsoil) because the viscosity at temperture is much better then Mobil-1 for the same weight oil. I would not go to a heavier oil then 10W30. However, his numbers really do look OK.

JWD01

35PSI @ idle, 47PSI @ 2000RPM. Water temp-196, Oil temp-200.

Fang S-289

That's consistant with what mine runs at, and always has. I don't know if that's good or not though.

C5 StockSwap

Just did my first oil change on a new 2002 Vert. After change (Mobil 1 5W-30 and UPF44), pressure is ~ 35 at idle, and in the 50's under throttle. From what I've seen, this is a normal reading.

GlockLT4

This is exactly what I've been looking for. What kind of difference are you getting with the Amsoil?

vettenuts

Never did a comparison, but when the factory drain went into the pan, the Amsoil went in.

JC in XTC5

25 PSI at idle is very normal. The GM service manual states the minimum pressure at 1500 RPM is something like 6 or 8 PSI (I don't have it in front of me but remember from previous questions it's in this ballpark. :flag

Katzey

Hello all! My gauge is pinned at 80. A mechanic friend of mine said, more than likely it's just the oil pressure senser. I checked the digital gauge and it's reading 117psi. What should the readings be at? It would normally be reading around 30 on the needle gauge, but the 117 has me concerned. Will I be able to drive this to my shop for repair? Any ideas? Thanks.

redzg

Sending unit. Drive to the repair shop, or do the repair yourself, many an instruction set and suggestions for remote mounting of the sending unit, should it fail again. A couple of threads that note which replacement sender is the best.

Katzey

Thank you very much for your input. I was just nervous to drive it for about a half hour, 8 miles to work.