Working on an oil pressure warning and issue on my 09. Determined it was the oil pump pickup O-ring, which is a relatively common problem on the LS engines like in the Hybrid and other GM vehicles. Since dropping the oil pan is such a pain, thought at 200K miles I would change the oil pump too. The LS engines with AFM (4 cyl mode) have specific pumps which have more volume. However when searching for the correct on for the Hybrid, found that Melling (a high quality perfromance oil pump supplier) does NOT have one for the Hybrid, and in the notes states something about a variable displacement vane pump. So does they Hybrid use a specific pump and can the high volume ones for other applications be used? I suspect the variable displacement pump is for fuel economy reasons, like many of the other parts on the Hybrid.

 

typical issue is the o ring in the pickup tube I suggest changing out the sensor and screen as well...

 

OEM Oil pump for the 6.0 tahoe hybrid. (Mine is a 2009) is 12623423
https://www.gmpartsdirect.com/oem-pa...-pump-12623423
According to my dealer they are different from the normal 6.0 pumps.

I just happen to be looking it up this morning. Oil pressure dropped to 0 on the wife headed in this morning. (if she revs the engine it gets up to 40 so its not the pressure transmitter.)
Last time this happened dealer diagnosed a relief valve in the oil pan. It seemed to fix the problem for a year but now its back. I'm going to have a pump replaced while they're in there since its at 220,000 miles.

This thing is amazing in deep snow and its in good shape so I think its worth throwing the money into it.

 

Try putting an extra 2 quarts of oil in and check pressure. If that fixes it then the oil pump pickup tube O-Ring is leaking and letting the pump suck air. $5 O-ring, but a pain in but to change. Have to pull front diff, loosen electric steering rack, and pull oil pan. Fixed my 09.
Don't be driving it much with that extra oil, that can be detrimental. The extra oil covers the O-ring area to prove it is sucking air there.
Its a common problem on the LS engines like on the Hybrid and other GM trucks and cars.

 

This condition originally occurred last year. dealer diagnosed the oil pan pressure relief valve failed. I paid to have that replaced an asked him to replace pickup tube o-ring while he was in there. ( extra 20 bucks)
I called dealer yesterday. They have a 12 month 12K mile warranty on the repair work. I'm currently sitting at 11.5 months and 10k miles..... WHEW!!!!!! YES!!!!!!!
The pan has to be dropped to get to the relief valve. (I'm sure he'll come to the same conclusion) Think I'll have them replace the oil pump while he's in there. At 212k miles its time. need to do battery next.

 

These old hyrbrid vehicles are almost hypnotic, they make you spend money on them because of the illusion of it being a worthwhile investment. LOL just kidding (kinda)
I am getting rid of this one on October 15th 2021 when I retire sell price is $6,600.00 just what I gave for it a little over 2 years ago. Go ahead and start lining up to purchase..................... you will be assimilated.