My truck is a 04.5 ram 2500 HO 5.9. The oil pressure gauge reads about 3/4 when cranked at idle but once warmed up at idle it falls in between low and half way but as soon as you give it fuel it jumps quickly back over halfway is this normal. Heard some people say it was normal that gauge is like a dummy gauge.Thanks for any help.

 

Mine goes up and down between idle and cruise RPM. It does not 'jump' up but goes up and down fairly steadily. I wouldn't worry about it. Just use it now as the benchmark for watching what happens later down the road. Any change means you may have to get some diagnostics done. I have never heard of a Cummins giving oil pump/pressure problems though.

 

The guage is a dummy run by the computer as long as you have 6psi.

Looks OK to me. Pressure on a warm engine can drop to 20psi at idle and as high as 80psi on a cold engine at higher RPM's. At highway speeds on a warm engine mine runs around 50psi. The dummy guage in most cases reads fairly close to the real guage except at idle, then it reads more than the real guage.

I may have saved an engine at work when I noticed that the oil pressure was dropping below what was normal (on a real guage). Took it to the mechanic and we checked the oil. Crankcase was full of diesel. A dummy guage would not have shown this drop in pressure. This is one of the reasons I installed a real pressure guage.

 

Thanks for the info.