harleygreg

Folks, I really appreciate your input and advice! Here's where I am.

Issue - little or no oil pressure 12psi @1200rpm) on my rebuilt 2004.5 Cummins 5.9

What I've done to date:
1. replaced oil pump, suction tube, oil cooler & gaskets, cleaned and oiled pressure release valve.
2. verified that I have oil flow (removed filter and oil flowed into bucket)
3. checked oil and it is getting darker so it is circulating but little to no pressure

This weekend I am going to pull it out again and looking for any advice on what I should look at/check for, etc. Need to get this back on the road asap!

Thanks!

madhat

Did you put a gauge on it, or are you relying on the gauge in the cluster?

harleygreg

Yes I have a new OP gauge and I hooked up another manual OP gauge on the oil filter top. The stock one goes to 40 for a few seconds then drops to 0. The other 2 show about 4-5 at idle and 12-15 at 1200rpm. I only run it for about 30 - 45 seconds maybe a minute.

StealthDiesel

I would not run that engine with that low of oil pressure.

Was it running ok when you did start it? I'm thinking a camshaft lifter, or broken pushrod or broken rocker arm...

Assuming the bearing clearances are correct for your rebuilt engine....

The Cummins oil pump/filter pressure relief valve is in the oil filter head cooler assembly bolted to the side of the block.
I know you mentioned you have cleaned and checked it but I suspect this is where the problem lies.

Good luck and please post back what you find..

harleygreg

Found the problem! Oil Block plug on front face by cam bushing blew out! I used Permatex Indian Head. Any ideas to make sure it doesn't come out?