My 6.5L turbo has some strange oil pressure behavior.
The history: It had always run about a steady 40psi on the highway for the longest time. A while back I had to change the sensor and it started running a bit higher but in idle it would drop to almost 0, so low that the check gauges light would come on.
Now in the few days I have started getting really high readings. Almost 80psi (almost pegged out) at 60 mph but it is only dropping to 10 psi in idle. Also when I shut off the engine the gauge stays at 10psi. Turn the key to engage the electrical (but not crank) and the gauge will drop to 0.
Any ideas??
Also, is there any motor flush (add to oil) I can use on this turbo diesel?

 

Where did you get the OPS? If you didn't use a AC/DELCO it's junk.

 

I would have that sensor warrantied out.

 

X's2. Also use a mechanical oil pressure gauge to verify that you have good pressure.

 

If it is a big parts house OPS and he switches it out for another parts house OPS it will fail again I can't say it enough that AC/DELCO is the only OPS that belongs in the truck you can get one at the dealership for about $30 I had to replace mine back this spring a extra $10 goes a long way sometimes the previous AC/DELCO OPS that was in my truck lasted 12 years.