08 'Hoe w/ low oil pressure

[Joe Hudson]

Much experience and wisdom has been shared on this topic so no rehash here, more a stream of unconsciousness. Vehicle is an '08 Tahoe 5.3L 4WD with AFM @ 204k miles and it's issued a second 'low oil pressure' DIC warning. Both happened at cold start, in an unheated garage, but now the one lifter that always ticks and then quiets soon after cold start is not getting quiet anymore - and this spooks me more than the code. I am the original owner and performed all oil changes with Mobil 1 and AC Delco filters @ ~ 50% oil life... and a few cans of MOA included over the years.

Anyway -

- am going to change the oil filter (oil is at 80%) and see if the error and noise go away
- if not, add a couple quarts of oil, point the Hoe down the drive and see if the pressure comes up / the tick goes away (to test the pickup 0-ring)

Assuming the 2 Qt test resolves the issue, I'll find a local I can trust to confirm - that is, physically test the (low) pressure and then perform the o-ring work (shocks are one thing... dropping half shafts and the diff and the pan while laying on my back is for the youth among us).

While the o-ring is being fixed, I'll probably have the pressure sender and screen replaced as 'not cheap' insurance. Obviously, the oil pump itself could be bad - I'd still do the o Ring and sender.

A Q if you're still reading - doesn't a bad oil pump grind or leak or ??? I've had bad water pumps that rattled - but maybe oil pumps fail silently?


Many thanks to those who share and who moderate.

 

[alpha_omega]

I know you mentioned getting some work done soon, but have you previously done any of the work for the TSB [Bulletin No.: 10-06-01-008F] updating the Valve Cover, AFM deflector shield, pickup tube, o-ring?
Have you replaced the oil pressure sensor and screen or will this be the first time doing so? Also, are you running a catch can - have you noticed any loss of oil in addition to your loss of pressure?

One caveat for your lifter tick, and I’m not saying you’re wrong, but I have seen guys get that sound confused with the tick caused from broken manifold bolt(s). If you check both sides, usually the very front and rear bolts (LH side) and the rear bolt on the (RH side) are the culprits for that problem. You may have both a stuck lifter and broken manifold bolts.

 

[Joe Hudson]

Thank you A_O... the bulletin has not been performed nor have I ever replaced the sender and screen... the vehicle consumes (burns) about 1/2 to 1 qt of oil between changes.

I gravitated to the lifter tick being oil pressure related from its behavior... noisy and then quiet in 15-20 seconds after cold start (plus I am old and old people carry crap in their heads - hydraulic lifters need oil delivered under pressure I think?)

From the above - a new oil filter did not restore pressure but 2 qts of oil did... never even got out of the garage to point the nose downhill but at idle the pressure is now 30-40 ish.

The shop I will take it to is ~ 15 miles away - I believe I can avoid a tow bill as long as I'm gentle getting there and watch the gauges.
(once again, this Forum proves its worth)

 

[89Suburban]

Last winter I was driving down a highway and got off onto a rural road and I got a loud lifter noise. I freaked out and pulled into a parking lot and shut it off to check the oil. Oil pressure was fine when this happened. Oil level was fine. LOUD ass lifter tick when I started it back up. I revved the sh*it out of it to like 6 grand and it disappeared and been fine since LOL WTF...

This WAS with the Range device installed. So it was not changing modes. Just a freak thing? Dunno...

 

[iamdub]

Much experience and wisdom has been shared on this topic so no rehash here, more a stream of unconsciousness. Vehicle is an '08 Tahoe 5.3L 4WD with AFM @ 204k miles and it's issued a second 'low oil pressure' DIC warning. Both happened at cold start, in an unheated garage, but now the one lifter that always ticks and then quiets soon after cold start is not getting quiet anymore - and this spooks me more than the code. I am the original owner and performed all oil changes with Mobil 1 and AC Delco filters @ ~ 50% oil life... and a few cans of MOA included over the years.

Anyway -

- am going to change the oil filter (oil is at 80%) and see if the error and noise go away
- if not, add a couple quarts of oil, point the Hoe down the drive and see if the pressure comes up / the tick goes away (to test the pickup 0-ring)

Assuming the 2 Qt test resolves the issue, I'll find a local I can trust to confirm - that is, physically test the (low) pressure and then perform the o-ring work (shocks are one thing... dropping half shafts and the diff and the pan while laying on my back is for the youth among us).

While the o-ring is being fixed, I'll probably have the pressure sender and screen replaced as 'not cheap' insurance. Obviously, the oil pump itself could be bad - I'd still do the o Ring and sender.

A Q if you're still reading - doesn't a bad oil pump grind or leak or ??? I've had bad water pumps that rattled - but maybe oil pumps fail silently?


Many thanks to those who share and who moderate.

Thank you A_O... the bulletin has not been performed nor have I ever replaced the sender and screen... the vehicle consumes (burns) about 1/2 to 1 qt of oil between changes.

I gravitated to the lifter tick being oil pressure related from its behavior... noisy and then quiet in 15-20 seconds after cold start (plus I am old and old people carry crap in their heads - hydraulic lifters need oil delivered under pressure I think?)

From the above - a new oil filter did not restore pressure but 2 qts of oil did... never even got out of the garage to point the nose downhill but at idle the pressure is now 30-40 ish.

The shop I will take it to is ~ 15 miles away - I believe I can avoid a tow bill as long as I'm gentle getting there and watch the gauges.
(once again, this Forum proves its worth)

Oil pumps rarely fail. They're just too simple and are constantly lubricated. The pressure relief valve in them is more likely than anything to fail. Their usual failure is getting stuck open, either from a failed spring or the valve getting wedged open from a piece of debris in the oil. All very small chances of happening, though.

At 200K+ miles, you're doing pretty well to only burn 1/2 to 1 quart between changes, assuming these are longer than 3,000-mile OCIs. You seem to have nailed a diagnosis for a failed O-ring. There are a few updates you could perform along with this work, but I wouldn't spend the money on anything AFM-related, such as the deflector shield or updated VLOM. Instead, have AFM turned off in the tune. You can have this done for about $60 by mailing off your PCM (HERE) and waiting a few days or for around $100-$150 by having a local tuner do it. They could do a few other quick and easy things (deleted speed limiter, turn off some emissions-related codes, etc.) if you need and wanna get the most for that $100+.

I agree with confirming the ticking to be a lifter and not an exhaust leak. They both present very similar symptoms- ticking when cold that decreases with time/warm-up, etc. To help confirm it's a lifter that's ticking, at the next cold start, hold the throttle pedal to the floor while you hold the key in the cranking position. It'll automatically stop cranking after about 10 seconds. Let the starter cool for about a minute, then repeat. Do this a total of 2-3 times, then release the pedal and start the engine as normal. If the ticking is reduced in severity and/or duration, then it's definitely a drained lifter.

Getting the updated driver side valve cover and a catch can are HIGHLY recommended. But, you can install these yourself after the O-ring replacement.

 

[alpha_omega]

Thank you A_O... the bulletin has not been performed nor have I ever replaced the sender and screen... the vehicle consumes (burns) about 1/2 to 1 qt of oil between changes.

The shop I will take it to is ~ 15 miles away - I believe I can avoid a tow bill as long as I'm gentle getting there and watch the gauges.
(once again, this Forum proves its worth)

That’s damn good consumption for not having the updated valve cover or running a catch can.

Oil pumps rarely fail.

I agree with confirming the ticking to be a lifter and not an exhaust leak. They both present very similar symptoms- ticking when cold that decreases with time/warm-up, etc. To help confirm it's a lifter that's ticking, at the next cold start, hold the throttle pedal to the floor while you hold the key in the cranking position.

I’m glad I read your response because I was going to mention the same trick. You can also use a stethoscope or a long skinny screwdriver to listen for the sound if you have an ear for that kind of thing.
I wouldn’t necessarily put the money into AFM either, I was just curious as to what work/maintenance the stealership may have preformed in the past.
Potentially you could have broken manifold bolts as well, but that definitely wouldn’t be your primary concern. The exhaust tick usually goes away much faster after a cold start and is obviously much less problematic than a lifter.