High oil pressure question

[Arcan]

Greetings to all - I'm a new member and also new to diesel vehicles. I just inherited a 1984 G2500 van camper (in great condition) and I've noticed something odd about oil pressure.

The guage has a max value of 550 kPa. When running at speed the pressure reads between 275 (middle) to about 3/4 of the guage. I recently went winter camping and left the engine running all night. When I awoke in the morning I noticed the guage was at 550 (max)! When I revved the engine slightly the pressure went back down to ~3/4 of the guage. The engine runs fine and sounds normal.

I tried to do a little research by buying a service manual from GM but was told it's not available.

Any thoughts on this would be appreciated.

[Robyn]

Hello and Welcome to TDP

Helm is the source for the manuals (On line)

The issue is most likely a flakey sending unit or gauge. The gauges in the older rigs can get goofy over time.

Also the cicuit mylar can get corroded behind the cluster and then things go astray. The traces lose contact and sometimes they dont ground good and things really get wierd.
Try installing a new sending unit first, if this is to no avail look over the connections at the gauge and or install a manual gauge in tandem as a reference.

The 6.2/6.5 family should run at around 40-50 PSI hot and idle at around 20 PSI

Every truck and year model will show slightly different readings on the gauges due to production tolerances in the equipment.

These electric gauges are guess meters and good for reference only.

If you see large anomalies its best to use a direct reading gauge to check things.

Hope this helps

Robyn