Oil Pressure

[Chrisman889]

Anyone know what "normal" oil pressure would be in an 85 Suburban with a 350? My gauge fluctuates from 15 to 30 at max. Engine runs fine but that seems kind of low to me.

 

[zora]

rule of thumb is 10 psi per 1000 rpm, 3000 rpm 30 psi, 4000 rpm 40 psi, etc. What viscosity oil are you using and how many miles on the engine?

 

[Chrisman889]

10w40 not sure on the miles, odometer reads 351k but that was from the diesel that was in it. Now there is a 350. I think it's about normal.

 

[VanGo]

Not the truck, the engine. Is it a rebuilt 350? Salvage? That seems low if 15-30 is the range you get. Mine is about 55psi on the highway.

 

[Chrisman889]

It's a salvage I believe, it goes to about 40 at 55mph. Then again it's an after market gauge and may not be hooked up correctly. All of it came in the truck when I bought it. It runs really well, I could set a glass of water on the air cleaner and have almost no ripples in the water.

 

[Chuzz]

I wouldn't worry about it too much. As long as you can't hear any knocking from the pistons or clicking in the valve train, you should be okay. SBC engines can run on very low oil pressure for a LONG time. I had a buddy with a 327 years ago and he said as long as it had 5lb of pressure, it was fine. And no, I have no personal experience with one as I've never owned one. Just going by what I've read. Get yourself another gauge and check it that way, but 40 psi is an acceptable reading as far as I know.

 

[Chrisman889]

It seems to drop as the engine heats up. When I start it goes up to 40 and as I drive and engine comes to temp it drops to 30-35, that makes me worry a little, maybe losing pressure somewhere as things heat up.