6.2 hot idle oil pressure.
09-23-2017, 03:35 AM
#12
Staging Lane
That relief valve is there to provide consistent oil pressure to the VVT cam phaser so it can reliably advance/retard the cam right? (Same thing with the DOD in the 5.3 right)
09-23-2017, 10:39 AM
#13
The relief is there because GM uses the same oil pan across the board on the trucks..... hell they do it on the cars too. The LS3 has no VVT or AFM and it still has the relief on the Camaro's at least because they use it on the L99. The only reason I have been told it is there is for Active fuel management and limit the upper end of the oil pressure spectrum for the lifters. Is it there for VVT? I don't think so... the oil pressure swings are the same up until above whatever it relieves at and you can see it's different for everyone. By 55 psi the cam would be at max retard anyhow lol.
I like how they really didn't change anything with the AFM system or the VVT on the Gen V engines and they will peg the gauge at WOT.. they do run an electronic relief that limits oil pressure to about 3700 rpm and then it closes and allows the engine to make whatever it will above that.
https://www.performancetrucks.net/fo...-valve-523970/
There is a GM explanation on that thread and they specifically call it the Active Fuel Management oil pressure relief valve. On the later ones they have a shroud around the bottom of the relief that directs oil back into the pan. My LS3 has the shroud but the older gen IV truck engines I had ( newest was like 08/09) did not.
I like how they really didn't change anything with the AFM system or the VVT on the Gen V engines and they will peg the gauge at WOT.. they do run an electronic relief that limits oil pressure to about 3700 rpm and then it closes and allows the engine to make whatever it will above that.
https://www.performancetrucks.net/fo...-valve-523970/
There is a GM explanation on that thread and they specifically call it the Active Fuel Management oil pressure relief valve. On the later ones they have a shroud around the bottom of the relief that directs oil back into the pan. My LS3 has the shroud but the older gen IV truck engines I had ( newest was like 08/09) did not.
Last edited by 1994Vmax; 09-23-2017 at 10:47 AM.
09-23-2017, 01:26 PM
#14
Staging Lane
The relief is there because GM uses the same oil pan across the board on the trucks..... hell they do it on the cars too. The LS3 has no VVT or AFM and it still has the relief on the Camaro's at least because they use it on the L99. The only reason I have been told it is there is for Active fuel management and limit the upper end of the oil pressure spectrum for the lifters. Is it there for VVT? I don't think so... the oil pressure swings are the same up until above whatever it relieves at and you can see it's different for everyone. By 55 psi the cam would be at max retard anyhow lol.
I like how they really didn't change anything with the AFM system or the VVT on the Gen V engines and they will peg the gauge at WOT.. they do run an electronic relief that limits oil pressure to about 3700 rpm and then it closes and allows the engine to make whatever it will above that.
https://www.performancetrucks.net/fo...-valve-523970/
There is a GM explanation on that thread and they specifically call it the Active Fuel Management oil pressure relief valve. On the later ones they have a shroud around the bottom of the relief that directs oil back into the pan. My LS3 has the shroud but the older gen IV truck engines I had ( newest was like 08/09) did not.
I like how they really didn't change anything with the AFM system or the VVT on the Gen V engines and they will peg the gauge at WOT.. they do run an electronic relief that limits oil pressure to about 3700 rpm and then it closes and allows the engine to make whatever it will above that.
https://www.performancetrucks.net/fo...-valve-523970/
There is a GM explanation on that thread and they specifically call it the Active Fuel Management oil pressure relief valve. On the later ones they have a shroud around the bottom of the relief that directs oil back into the pan. My LS3 has the shroud but the older gen IV truck engines I had ( newest was like 08/09) did not.
10-12-2019, 06:19 PM
#15
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Help! 6.2 liter low oil pressure!
I have a 2007 Yukon XL Denali 6.2 liter. I have replaced the oil pressure sensor, the oil pickup tube and oring, oil pump, and deleted the relief valve and the truck still has issues. The oil pressure is around 55-60 when cold. As the engine reaches operating temp, the oil slowly drops. Once the engine reaches operating temp the most it will build is around 25 psi. At idle it will drop to around 0-5 psi. I don't know what else to change at this point. Any ideas?
10-12-2019, 06:35 PM
#16
I have a 2007 Yukon XL Denali 6.2 liter. I have replaced the oil pressure sensor, the oil pickup tube and oring, oil pump, and deleted the relief valve and the truck still has issues. The oil pressure is around 55-60 when cold. As the engine reaches operating temp, the oil slowly drops. Once the engine reaches operating temp the most it will build is around 25 psi. At idle it will drop to around 0-5 psi. I don't know what else to change at this point. Any ideas?
10-13-2019, 12:09 AM
#17
An old necro thread of my own lol. Well now I own a 6.2 as well being a 2013 L9H max trailer extended cab. Oil pressure is better than the one back in 2017 but still crap. I measured the pressure manually at the oil filter and it varies from the sending unit by 15 psi at times or more lol. I trust my annually calibrated 5000 dollar deadweight a lot more than GMs 20 dollar transducer. I swapped sending units and it reads the same. The engine has a weird dull thud in the bottom end and oil analysis showed higher than normal iron in the oil. This truck has around 57000 miles on it to boot. Gives me an excuse to try and use the new 6.6 rotating assembly (not pistons obviously) in my other core 6.2 and build an LS 6.6.
10-30-2019, 09:11 PM
#18
Ive heard of this happening on afm only engines as well. Which cam bearing need to be changed? Just the first one? Just wanted to know just in case i run across the problem. Can it be done inside the truck?
11-02-2019, 12:20 PM
#19
Well my L9H gets worse by the day. Now it has a loud rattle on cold start that takes a good minute to quiet down so it can warm up and go into it's normal dull thud it makes lol. I am glad I don't actually care because if some average poor schmuck bought this truck they would be losing their mind over paying likely a dealer to put a long block in it. Me though.... it's more how long can it make these noises and still not use oil, run extremely hard for a stock tune to 5800 rpm and last haha.
11-03-2019, 01:21 AM
#20
Well my L9H gets worse by the day. Now it has a loud rattle on cold start that takes a good minute to quiet down so it can warm up and go into it's normal dull thud it makes lol. I am glad I don't actually care because if some average poor schmuck bought this truck they would be losing their mind over paying likely a dealer to put a long block in it. Me though.... it's more how long can it make these noises and still not use oil, run extremely hard for a stock tune to 5800 rpm and last haha.
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