Just wondering if you could shim the oil pressure relief valve to get more oil pressure? If so where is it located? I see the NORMAL 25 psi at idle, I would like to see at least 35 psi at idle.

Don't know about shimming, it must be a spring/plunger design, if that's true, you could put a "slug" in the cap to increase spring tension on the plunger. My manuals show it located at the right front of the block at the forward end of the passenger side main oil gallery drilling. Maybe one of the "techs" who've been over these engines inside and out can answer for sure - DMaxAlliTech? MaxPayne? Bueller?

Does the truck run fine and noise free at 25psi?? Then leave it alone! :) there is no problem with the duramax's oil pressure. Minimum spec at idle is 14psi. Pressure isnt everything. You need volume... ;)

I would rather be at the maximum specification, If I have enough volume at 60 psi At 2000 rpms I think I would have enough at 35 psi at idle and say 70 psi at 2000 rpms. Just a thought at this point anyways.

Like I have seen on this forum before about the pressure thing, Smokey Yunik once said 10 psi for every 1000 rpms, and everyone says their oil pressure is 25 at idle and 50-60 when running down the road. My 03 has 162K and still going strong with 1 set of injectors at 36K.
Change your oil and filters and warm it up before putting a load on it is my motto.

Smokey Yunik once said 10 psi for every 1000 rpms, and everyone says their oil pressure is 25 at idle and 50-60 when running down the road.........Change your oil and filters and warm it up before putting a load on it is my motto.


:exactly: x2 .....thats good common sense right there Tolliwacker

on edit...the down side to high oil pressure is that when the weather turns cold it can be awfully hard on seals etc.

Shimming the oil pressure relief valve ain't gonna change oil pressure at idle. All it will affect is oil pressure at it's max at a higher rpm. Then you may find yourself with some extreme high pressures at cold startup. Ever seen the mess when an oil filter ruptures?:eek:
The DMax has a system that flows an extreme amount of oil since it uses a system of oil jets to spray oil from jets on the crank and rods on to the bottom of the pistons to cool them (the pistons).
These jets bleed off a lot of oil, and at idle on a warm engine the relief valve is shut tight.
Dave