LLY: Sporadic Low Oil Pressure

[Triple L]

Hay guys, So I've been having these troubles on and off lately, every now and then I'll pull up to a stop light and all the suddon my truck has very low oil pressure, At this level I'd assume it should come up on the DIC with a warning of low oil pressure but nothing comes up so I kinda thinking its the guage but I dont know.... If I rev it up to 1500 rpm then it goes to where it normally sits, If i turn the truck off and restart it everything is good again, Oil level is normal and it only happens every now and then, but if i leave it, it will get to about 60 lbs at 2500 rpm so its seems like its still building pressure but has very little at idle... I've done a seach and havent came up with much... And tips on where to look or what might be the culprit would be greatly appreciated...

 

[duratothemax]

Seems normal for an LLY/LBZ/LMM engine when its hot/warmed up. They really dont have great oil pressure hot at idle; its more of a high volume low pressure system. IIRC it turns on the low oil pressure warning (the chimes ding at you and it says "LOW OIL PRESSURE" in the driver info center) at 7-10psi.

They normally run just outside the red zone hot at idle. What oil are you running? Regular 15w-40?

Minimum allowable spec (according to GM/Isuzu) is 14psi hot at idle, and 42psi hot at 1800rpm.

ben

 

[Triple L]

Thanks for the info, but I've owned this truck for a while and its always sat 2 more little notches up, or just a little bit below the first big notch on the guage, and now it spuratically goes down this low, So Im kinda thinking somethings not 100%.... Im running Rotella T 15-40

 

[Lb7KID]

maybe somethen in youer oil pan that the pick up tube sucks up every now and again?

 

[z79outlaw]

Thanks for the info, but I've owned this truck for a while and its always sat 2 more little notches up, or just a little bit below the first big notch on the guage, and now it spuratically goes down this low, So Im kinda thinking somethings not 100%.... Im running Rotella T 15-40

The gauge could be finiky, do you have EFI live or somthing else you can check with.

 

[RENODMAX]

The gauge could be finiky, do you have EFI live or somthing else you can check with.

x2. That's what mine did

 

[Triple L]

The gauge could be finiky, do you have EFI live or somthing else you can check with.

I have a friend who has it... What would I be checking for, to see if what efi live shows matches up with the guage shows to see if its the guages problem or if the guage is actually correct?

It ticks me off, The ppe tuner shows alot of stuff on the diag. mode but dosent show oil pressure....

 

[z79outlaw]

I have a friend who has it... What would I be checking for, to see if what efi live shows matches up with the guage shows to see if its the guages problem or if the guage is actually correct?

It ticks me off, The ppe tuner shows alot of stuff on the diag. mode but dosent show oil pressure....

Exactly that. Im willing to bet you'll find the answer by doing that.