2008 6.0 Vortec, low oil pressure?

0burb8

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I also found some specs that I've never seen before. I'm not sure that are these from GM though.


LY6
1,000 RPM 22psi min.
2,000 RPM 30psi min.
3,000 RPM 33psi min.
 
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I had a 2005 C2500 with the pre VVT 6.0. Little over 100k, not too sure of the maintenance history, but pretty sure oil was changed at quick lube places at OLM intervals. Very low oil pressure, verified with a mechanical gage.
Changing out the oil and filter did nothing.
As mentioned above, replacing the oil pump wasn't the trivial task of just dropping the pan. Front of the engine covers have to come off along with the crankshaft pully. With a new OE pump, o-ring, etc. nothing changed. Had too many projects at the time, along with an over full time job, so I sold the truck as is. My suspicion was excessive bearing wear, but never did find out what caused the problem.
 

0burb8

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I had a 2005 C2500 with the pre VVT 6.0. Little over 100k, not too sure of the maintenance history, but pretty sure oil was changed at quick lube places at OLM intervals. Very low oil pressure, verified with a mechanical gage.
Changing out the oil and filter did nothing.
As mentioned above, replacing the oil pump wasn't the trivial task of just dropping the pan. Front of the engine covers have to come off along with the crankshaft pully. With a new OE pump, o-ring, etc. nothing changed. Had too many projects at the time, along with an over full time job, so I sold the truck as is. My suspicion was excessive bearing wear, but never did find out what caused the problem.
Yeah, I know that it has to be done like you said. Just didn't know that you can change the oil pump without taking the oil pan off, but you can.

The way I see it, if I go through the trouble to change the o-ring, would be stupid not to change the oil pump because you can access them both from the front of the engine, because that's an relatively cheap part IMO. And my buddy is a very skilled mechanic so no problem.
But yeah still debating on that.
 
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I agree that changing out the pump and o-ring is the logical next step.
The one thing I didn't do that I read about later was to make sure the oil passage to the pressure sensor was unobstructed. I believe you can make sure the passage is clear with pipe cleaners. In my case, the noise the valves made at idle convinced me the oil pressure was, in fact, low, and it wasn't just a reporting problem.
 

0burb8

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Well I think I made up my mind for now.
Spending a day reading different forums, my gut tells me that I have no major reason to sweat it.

Also found out that the stock oil pump pressure relief valve starts opening at 33psi. So you should not see crazy psi readings when you think about it.

I'm going to do an oil change soon though, before I go on a 1500mile trip with family.
I thought that I'd try running 5w-40 with an AcDelco UPF48R oil filter, great feedback on using that filter.
Using 5w-40 should bring the hot pressure up a little.
 
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Yeah, I know that it has to be done like you said. Just didn't know that you can change the oil pump without taking the oil pan off, but you can.

The way I see it, if I go through the trouble to change the o-ring, would be stupid not to change the oil pump because you can access them both from the front of the engine, because that's an relatively cheap part IMO. And my buddy is a very skilled mechanic so no problem.
But yeah still debating on that.

You cannot remove the Pick-Up Tube bolt from the oil pump without at least lowering the oil pan. This applies to all GMT800 & GMT900 platform trucks. Other platforms use the "upper" bolt hole in the pump body & can be unscrewed with the oil pan in place.

If you crack the oil pan loose.....It will leak from now on 'til you replace the gasket.

I'm sure someone has ground out the oil pan or pried on the pick-up tube, Hopefully you won't do that.
 

0burb8

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You cannot remove the Pick-Up Tube bolt from the oil pump without at least lowering the oil pan. This applies to all GMT800 & GMT900 platform trucks. Other platforms use the "upper" bolt hole in the pump body & can be unscrewed with the oil pan in place.

If you crack the oil pan loose.....It will leak from now on 'til you replace the gasket.

I'm sure someone has ground out the oil pan or pried on the pick-up tube, Hopefully you won't do that.
That's how they do it on Youtube.. Lol.
Thanks, very useful info.
 
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I don't believe the gauge is reading oil pressure at all. I think the oil pressure switch only signals the computer 2 or 3 pressure thresholds, and the computer just dials up the gauge to whatever it calculates pressure should be at that temperature and RPM as long as the sensor has met the expected threshold. If you really want to know the pressure, you have to put a mechanical gauge on it.
 

0burb8

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I don't believe the gauge is reading oil pressure at all. I think the oil pressure switch only signals the computer 2 or 3 pressure thresholds, and the computer just dials up the gauge to whatever it calculates pressure should be at that temperature and RPM as long as the sensor has met the expected threshold. If you really want to know the pressure, you have to put a mechanical gauge on it.
Is this just your own thought, anything to back it up?

I would like to know more about this, because seems like nobody on the face of the internet has solid information about this issue. Tiny pieces of a puzzle here and there, and you can't know which is accurate.
Amazingly no accurate information, as so huge number of people deal with this issue.

Somebody who worked/works in GM would be my best bet for accurate information.
 
Only AFM engines have that screen.
Not sure if that’s true, but in any case this is what the alleged screen looks like.

30D0E0F6-568A-477E-8014-20D5D06A3037.png
 
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Is this just your own thought, anything to back it up?

I would like to know more about this, because seems like nobody on the face of the internet has solid information about this issue. Tiny pieces of a puzzle here and there, and you can't know which is accurate.
Amazingly no accurate information, as so huge number of people deal with this issue.

Somebody who worked/works in GM would be my best bet for accurate information.
It has been discussed on here in depth...years ago by people with intimate knowledge of it's workings.
 
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5,253
Location
Fort Worth, Texas
I don't believe the gauge is reading oil pressure at all. I think the oil pressure switch only signals the computer 2 or 3 pressure thresholds, and the computer just dials up the gauge to whatever it calculates pressure should be at that temperature and RPM as long as the sensor has met the expected threshold. If you really want to know the pressure, you have to put a mechanical gauge on it.

2003 & up LSx engine use a Digital Pressure Transducer & are quite accurate, Though they have a high failure rate from the sensor shorting to 5-volts internally & actual gauge accuracy from stepper motor issues within the cluster can be questionable.
Scan data with a good OE sensor can be trusted within 5 PSI.
 

0burb8

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Update. Replaced pickup tube o-ring. Apparently, at some point someone already did it. You could tell that the oil pan has come off before, at least. Old o-ring was fine, maybe a little loose on the tube.
Very little to none metal particles in the oil pan when we went through the sludge with a magnet.

Switched to 5w-40 Maxlife fullsyn.
I gained maybe 5psi if you're optimistic, and lifter tap at cold start went away.

So I am satisfied with the job done.
 
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