isx oil pressure woes

I am not seeing any codes yet, but something is not right.

2013 579 Pete with ISX 15.

Once engine completely warms up going down the road, (water temp 180+/oil 220+) my max oil pressure falls to around 30 PSI. This at 70 to 75 MPH and 1500+ rpm. Also pulling it off the road hot slow idle is right around 18 or 19 before it start cooling off.

Working the turbo hard I lose maybe 2 PSI, using the jake It will sometimes jump up by that much.

Also getting a low pitched growling/rumbling between 1100 and 1300 RPM when pulling hills.


I am close to my oil change interval but no way should it read that low even with dirty oil.

No external leaks that I can see and no coolant in the oil.

It does seem to somehow empty thw coolant overflow every 40000 miles or so, low enough to trigger the warning light.

Any ideas?

FWIW, this is a rental truck specd without a manual fan switch, and that combined with Allstate Peterbilt leasing and their 20,000 mile oil change interval is sending this poor thing to an even earlier than normal grave I think.

 

Model cm 2250 if that makes a difference?

 

First time I have had a problem, oil is at 15000 miles now. In the past it has alwys managed to hold 34+ psi till 20000 miles.

 

I'm going to see how it runs empty right now from Baltimore to Canton, OH area. I am hoping you arw right and I dont end up with an engine in pieces after I pick up a load of bricks tomorrow...

 

It drops as low as 27 when climbing hills

 

What it oil pressure supposed to be at at slow idle and fast idle?