Oil Pump

[RZinKY]

Hi, I just bought a 99 3500 box van 6.5 turbo diesel. This is my second TD as I prev owned a 95 surb. I have noticed tha the oil pressure seem to jump around. most of the time the guage reads 40 a little higher on hwy and some times at idle 20. Is this typical or something to worry about.

Thanks Jeff :D


99 3500 211,000 miles 100,000 on motor (GM Replacement)

[Hubert]

Put an extra aftermarket gauge on it and see if its a real pressure fluctuation. Factory gauges are much better than warning lights but not great. 20 psi is lowbut I don't think will kill the engine catastrophically. Don't just take my word for it but I want to say bare minimum (at operating temp) is 10 psi per 1000 rpm for oil pressure (assuming good 15w-40 oil). Should be higher cold.

I would suspect a problem if oil pressure fluctuations were not temp related and rpm dependant.

[Robyn]

15-40 dino oil is the usual juice to feed these critters (Diesel rated)

Hot running on your dash gauge should read 40 or may a tad more depending on the gauge, the sender and the engine.
Idle normally will read down near 20 on your dash gauge but should pop up to 40 with just a slight jazz of the throttle.

The 6.2/6.5 family do not run real high oil pressure.

With a fresh engine and all things just right you might see 45-50 Lbs tops running down the road.

If your gauge is rather wiggly and eratic, change the OPS on the back of the engine by the LH head.

The sending units also run the fuel lift pump and have a habit of getting flakey.

A fresh OPS would probably solve your issues and also assure you of good lift pump operation as well.
Fairly cheap and easy to install on a van.

Good luck

Robyn