DD15 Low oil pressure

What's your odometer reading say?

If you're above 500k, it's a good idea to roll in new rod bearings to bring your oil pressure up, and while you're in there, roll new main bearings in too.

As the bearings wear, clearances increase allowing increased flow which reduces oil pressure.

The oil pump doesn't create pressure, it produces flow, and that resistance to the flow creates pressure.

If the tolerances between your bearings is excessive and worn, you will have less resistance, which equates to lower oil pressure.

I would suggest to park the truck and get this low oil pressure problem solved before you grenade your engine.

 

To roll in new Rods and Mains they need to drop the oil pan and drain the oil, so in the Fontana, CA area, Bearings, Oil Change and labor runs about $1200, and can be done in (1) one day.

The costs may be more or less in other parts of the Country.

A bad cylinder head isn't going to lower your oil pressure, the oil pressure may be low because of the continued overheating.

Do you have a bad cylinder head or head gasket too?

 

It has normal psi when it's cold because the engine oil is thicker when it's cold.

Once the engine and the oil heat up, it gets thinner, which makes your low oil pressure problem worse, especially in the summer time

Are you using 10w30 oil or 15w40?

I believe the Detroit recommended oil for the DD15 is 10w30 Semi-Synthetic for fuel economy and longer oil drain intervals.

You may temporarily solve your problem by using 15w40, but it's inevitable you may need new bearings.

 

you have to pickup o rings in the bottom have turned solid and dropping oil psi happens all the time on cascadias nothing new i would say to be on the safe side roll the rods and the mains as well since they already have to take the oil pan off to do the repair of the oil psi. nothing new o rings and gaskets oil and job and all cost about 800 can't remember the prices for the bearing of the top of my head but shouldn't be any more than 2500 with everything done

 

Coolant in the oil will cause the oil to get diluted, which in turn will make the oil thinner, so yes it may have lowered your oil pressure.

You can try changing the oil to 15w40 and see if it helps increase the oil pressure.