2011 tahoe with the LMG. A few years ago the hot idle oil pressure was around 30. A while back that seemed to drop to ~25, lately it's a little over 20. As soon as it's moving it's back to 40+ psi. The oil cooler block is leaking a bit which I'll be fixing soon, but I don't see that being the cause. Am I on the right track with putting a new pick up tube oring in it or should I be looking at something else?
20 psi oil pressure hot idle
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Marky Dissod
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Look again, then fix that leak, then look for others. Every leak lowers oil pressure.
Did you do the 'overfill by 2 quarts and point the nose downhill' test?
If oil pressure goes up, yes on the O-ring.
The only problem with the overfill and nose downhill test.... So that if the problem is the oil pressure relief valve in the oil pan, you're still left wondering. (They get weak over time, just like any pressure relief valve)
And yes, it could also be the pressure relief valve in the oil pump. I'd say drop the pan, replace the pressure relief valve in the pan as well as oil pump o-ring. Upon reassembly take care of that oil cooler line block gasket. I've had good luck with the felpro version.
And yes, it could also be the pressure relief valve in the oil pump. I'd say drop the pan, replace the pressure relief valve in the pan as well as oil pump o-ring. Upon reassembly take care of that oil cooler line block gasket. I've had good luck with the felpro version.
I need to do the passenger front diff seal anyways so I have a good excuse to get it out of the way and drop the pan. Would you suggest definitely getting the deflector while I'm putting a new valve in? Doesn't have any oil consumption issues as it is.
Also do you guys know what specific pick up tube oring I'l need? Seeing red, black, and green ones. Obviously want to have the correct one in hand so it can go back together same day but I don't really want to order all 3 if I don't have to.
swathdiver
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Mine has been doing almost the exact same thing. Also replaced the leaking oil cooler gasket the other day and that did not fix the low oil pressure once the engine is warmed up. We just changed the filter and oil too.
Oil pressure at idle in gear once warmed up is no lower than 19 psi.
At 212K, I guess she's just getting old.
Mine still has her original internals: oil pump, relief valve, o-ring, etc.
swathdiver
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DaveO9
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I just finished the o-ring replacement today in my 2013 with 207k. I explained in another post I was changing out the front diff carrier, so took the opportunity to do the o-ring at the same time. I was getting 20 psi hot idle too, maybe even a little lower. And 30 or under even at 2000k+ rpm. I'm at least 5 psi higher in those ranges now, maybe 10. I'll know more after I do some more driving in the next few days. (I did drive it enough tonight to get it to operating temp, and still at least 25 psi idle)
DaveO9
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Mine was black, Fel-Pro P/N 72401. Got it from AutoZone. One I took out was red.
You're 2010 model should have the deflector shield installed as OEM. Here's the neighbors that we did the AFM delete on last weekend:
Melling oil pumps come with each possible o-ring, and they give a pretty good explainer. If the end of your pickup tube does not get wider slightly where it goes into the pump, but it's the exact same diameter all the way to the end..... Then it's the black o-ring. If it widens out a little bit, then it's the red o-ring. I using micrometer to verify, but if you look carefully you can tell the difference with your eyes. Below picture is his red o-ring, if I remember correctly he was at about 192,000 miles. He was getting between 15 and 20 psi oil pressure. I'll throw in the picture where it shows the old one next to an oem Mahle that we were using to replace it:
Not only did the old o-ring look flat on both the inside and outside, it apparently shrank a bit. Pick up tube literally fell out of the pump once unbolted.
Get yourself one of the pickup tube girdles so you can use two bolts to hold the pickup tube to the pump. Inexpensive piece of mind.
Melling oil pumps come with each possible o-ring, and they give a pretty good explainer. If the end of your pickup tube does not get wider slightly where it goes into the pump, but it's the exact same diameter all the way to the end..... Then it's the black o-ring. If it widens out a little bit, then it's the red o-ring. I using micrometer to verify, but if you look carefully you can tell the difference with your eyes. Below picture is his red o-ring, if I remember correctly he was at about 192,000 miles. He was getting between 15 and 20 psi oil pressure. I'll throw in the picture where it shows the old one next to an oem Mahle that we were using to replace it:
Not only did the old o-ring look flat on both the inside and outside, it apparently shrank a bit. Pick up tube literally fell out of the pump once unbolted.
Get yourself one of the pickup tube girdles so you can use two bolts to hold the pickup tube to the pump. Inexpensive piece of mind.
.... Also, red and black and green colors referred to the OEM o-rings. There's no guarantee aftermarket, such as felpro, will be the same color correspondingly. (If you stick with OEM, then you won't be left wondering because the color is different on whatever brand you bought. Comparing old versus new is useless, as you can see above the old ones shrink. Mahle is the OEM, never had a problem using them. )
donjetman
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Over the yrs, I have successfully used both of the following o-rings in my 07 6.2L Denali stock pump and pickup tube.
Mahle# B32790 (installed 6/24)
and/or
Felpro# 72401 (installed 12/18)
See the taper? The pic is of the 5+ yr old Felpro still doing its job, but I changed it with the Mahle while I was in there.
Mahle# B32790 (installed 6/24)
and/or
Felpro# 72401 (installed 12/18)
See the taper? The pic is of the 5+ yr old Felpro still doing its job, but I changed it with the Mahle while I was in there.
donjetman
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I added the 2nd bolt, but didn't use the girdle.
Maybe next time?
Maybe next time?
Charlie207
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Yeah, I used one of these and some oil-resistant thread locker on the two screws for the pickup tube & girdle.
DaveO9
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Wow, wish I had seen this post a week earlier! I had no idea about the different styles of pickup tubes and that there were specific corresponding o-rings. Nor did I know about the availability of the girdle. (I was wondering what that second bolt hole was for). My tube is straight, no taper, and I used the black Fel-Pro, 72401. One I replaced was red. Any concerns?
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