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)

 

[swathdiver]

Me too, I'd heard about these engines but never owned one until last year. I grew around V6s mostly and in our minivans, only popped the hood to change the oil and air filters and the battery every couple of years.

 

[Doubeleive]

my nbs pretty much sat at 40 on the money, when I put in a new engine it sat at 70 for the first 20k or so then it settled down to about 60-65, my nnbs is retarded it jumps around anywhere from 25-50, I have read that having a external oil cooler like I have takes away about 10psi so I guess it's ok, it has a brand new engine in it so I hope so, lol.

 

[Charles Land]

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

On my 2001 5.3l Suburban, the "O" ring on the dip tube from the oil pump to the bottom of the oil pan wore out. First symptom was low oil pressure at idle, and the pressure gauge jumping around - very irregular pressure - due to sucking in air at the "O" ring along with of oil from the oil pan. Got steadily worse - replaced the "O" ring and problem solved - a few hours work an a $1 part. I have been told that is a common problem, especially on higher mileage vehicles - mine was over 250k at the time.

 

[frevnew]

On my 2001 5.3l Suburban, the "O" ring on the dip tube from the oil pump to the bottom of the oil pan wore out. First symptom was low oil pressure at idle, and the pressure gauge jumping around - very irregular pressure - due to sucking in air at the "O" ring along with of oil from the oil pan. Got steadily worse - replaced the "O" ring and problem solved - a few hours work an a $1 part. I have been told that is a common problem, especially on higher mileage vehicles - mine was over 250k at the time.

Yes, replaced the "O" ring oil pressure problem solved. Went from idling as low as 15 to only as high as 25. Now it is a little below 40 at idle and always above 40 when driving.

 

[Shaw520]

Well thats certainly something to keep in mind. Im not getting erratic pressure, just slightly lower than im used to. I must say though, if i had the pan off id surely upgrade the oil pump while in there.

 

[SlimJim]

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)

Did you figure this out? im having a similair issue.

 

[frevnew]

Well thats certainly something to keep in mind. Im not getting erratic pressure, just slightly lower than im used to. I must say though, if i had the pan off id surely upgrade the oil pump while in there.

I ended up changing the "O" ring on mine and added 15 to 20 lbs pressure. Ring was definitely worn. Long hour job especially on 4x4.

 

[SnowDrifter]

My 05 would have a hot oil Pressure of 33. as read via scanner. Like one tick below 40 on the gauge.

Have a high flow pump in there now and it's at a hair below 50 hot idle

 

[SteveB]

To change the oil pump you need to remove the timing cover.

Well thats certainly something to keep in mind. Im not getting erratic pressure, just slightly lower than im used to. I must say though, if i had the pan off id surely upgrade the oil pump while in there.

 

[Merc1973]

On my 2001 5.3l Suburban, the "O" ring on the dip tube from the oil pump to the bottom of the oil pan wore out. First symptom was low oil pressure at idle, and the pressure gauge jumping around - very irregular pressure - due to sucking in air at the "O" ring along with of oil from the oil pan. Got steadily worse - replaced the "O" ring and problem solved - a few hours work an a $1 part. I have been told that is a common problem, especially on higher mileage vehicles - mine was over 250k at the time.

Is there a write up in this job? Mine is a 4x4...