just added a mech gauge for oil pressure and it tells a different story than the dash. o/e reads 40+ at startup and dwindles down to 20+- at hot idle and stoplights. mech gauge reads 60+ at startup climbs to 80+- at high speed and can drop pretty low at warm idle or stoplight. can anyone tell me what average range of oil pressure is ok for these engines? thanks,,, great sight
98 12v 108k 4x 5spd bone stock

 

Minimum oil pressure should be no less than 25psi. I've been told by the Cummins Rep at the Mid-America Trucking Show that maximum is supposed to be governed at 70psi, but on cold starts I've seen close to 100psi before.

 

I have a mechanical oil pressure gauge too, on my 96, and I get the same readings you get. I think these readings are pretty normal. The OEM gauge is not very accurate.

 

After the truck is warmed up I see about 25 at idle and 65-70 on the highway.
Will

 

When I start my truck cold it is at 40 and when I start driving it is at about 50 if that. Is there something wrong with my truck? It has never really gotten all that high, even under heavy load.

 

mine is the same.

 

Minimum hot idle is 10psi. Minimum hot cruise is 25psi.