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GMT 900 Trucks General Discussion 2007 - 2013 Trucks | General Discussion

6.2 hot idle oil pressure.

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Old 09-14-2017, 08:42 AM
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No one to stir the pot, but my denali is about 35+ at idle with about 88k miles. Maybe mine was babied by the previous owner
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Old 09-23-2017, 04:35 AM
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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)
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Old 09-23-2017, 11:39 AM
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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.

Last edited by 1994Vmax; 09-23-2017 at 11:47 AM.
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Old 09-23-2017, 02:26 PM
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Originally Posted by 1994Vmax View Post
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.
Thanks for the clarification!
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