Oil Pressure ?

[Shaw520]

This is the first GMT that ive owned (04 Tahoe 5.3) that is showing under 40psi on the gauge,... (Ive owned over 15 different GMT's with mostly 5.7's, a couple of 454's, one 5.0 and now a Duramax) Now I know that these stepper gauge, especially the new ones, are notoriously very inaccurate,..so my question is what does the 5.3 typically show for oil pressure on the gauge.?

 

[HiHoeSilver]

This is the first GMT that ive owned (04 Tahoe 5.3) that is showing under 40psi on the gauge,... (Ive owned over 15 different GMT's with mostly 5.7's, a couple of 454's, one 5.0 and now a Duramax) Now I know that these stepper gauge, especially the new ones, are notoriously very inaccurate,..so my question is what does the 5.3 typically show for oil pressure on the gauge.?

Typical pressures for your truck are 40 at idle and up to maybe 60 on throttle. The sending units to bad and then usually the needle pegs at 80.

 

[Shaw520]

Typical pressures for your truck are 40 at idle and up to maybe 60 on throttle. The sending units to bad and then usually the needle pegs at 80.

I see,..well my gauge is reading 25psi at idle and up to 40 upon eccel.
Torque app does not read oil pressure meaning that it is not one of the readable perimeters from the pcm.

 

[mooman]

I am about the same. 19-22psi(I guess) at idle and 40psi when cruising once engine is hot. It just jump based on load on the engine, and when it is cold, I get 40psi and 60psi when cruising.

 

[HiHoeSilver]

I see,..well my gauge is reading 25psi at idle and up to 40 upon eccel.
Torque app does not read oil pressure meaning that it is not one of the readable perimeters from the pcm.

Dumb question, but how's your level on the dipstick?

 

[Shaw520]

Dumb question, but how's your level on the dipstick?

In the 'safe' zone . My experience with many SBC's is 40psi at idle,..60psi at rpm.
.

 

[swathdiver]

Oil pressure is fine and within specs. Are you the original owner? Later models used a pump that flow 1/3 more oil per revolution at a lower pressure. A scan tool reads oil pressure more precisely, it's dumbed down on the dash to keep people from freaking out and running to the dealer.

 

[Shaw520]

Oil pressure is fine and within specs. Are you the original owner? Later models used a pump that flow 1/3 more oil per revolution at a lower pressure. A scan tool reads oil pressure more precisely, it's dumbed down on the dash to keep people from freaking out and running to the dealer.

its an 04' Z71 Tahoe w/130k miles,..I am not the original owner,..this vehicle is newly acquired and the oil pressure has been like this since I bought it,... I dont suspect any real problems but was curious as to why so low compared to all my previous GMT's

 

[swathdiver]

A crummy oil filter can also deliver low oil pressure as does dirty oil too. The older engines had different springs that boosted the pressure up more. Plus your truck is 14 years old now as is that spring and pump. Keep an eye on it and swap it out for the Melling M365 or M295 when you're ready.

This is a great write up on Gen IV engines and also has a good explanation about oil pumps among other things:

http://www.enginebuildermag.com/wp-...es/03_01_2012/986163348GMGENI_00000054947.pdf

 

[Shaw520]

Looks like a good write-up SD,..a lot to learn about the new gen motors,... Im still living in the SBC era. (showing my age)