Truck oil pressure when hot idle little to none. No noise in motor been driving it like this for 2yrs. Towing a camper and more. New oil pump and timing chain and guides still the same. motor runs really strong. Checked with manual gauge installed an oil pressure gauge still same readings. Has an oil cooler . I am lost. Please advise me what to look for or test.

 

As you probably know, the factory gauge is not a gauge. If the pressure is 7 psig or about, it reads mid-scale. But, you said you have checked it with a manual gauge and it has little pressure at idle. What is the pressure at idle and when the engine is revved up? If it has 10 psig or more at idle, I wouldn't worry about it if the pressure goes up normally when revved. Could be the cam bearings or crank bearings are worn. What oil are you running? On an old higher mileage engine, I wouldn't hesitate to put some thicker oil in it such as 10w40.

 

What, exactly, does "still same readings" actually mean?

 

Idle PSI is around 10. Running down the road is around 25psi. If I stomp on it will go up to 75psi. Oil I have been using 5-30 Mobil one full synth.

 

Doesn't sound out of the range of pressures for an engine that's almost 20 years old presumably with tons of miles on it.. The only specification in the service manual is to check pressure at 2000 RPMs with everything hot. Should be 40-60 psi.

If that isn't achieved, most likely either the oil pump isn't pushing enough volume at pressure or there is excessive wear in the rest of the engine (crankshaft, main and rod bearings) so that the pump can't build higher pressures.

 

I think I would switch to 10w40 or some Rotella 15w40.

 

i will start out with the 10w 40. Thanks

 

I'd suggest doing the factory service manual test first so you know whether or not it's "in spec".

 

I have little to no oil pressure after the engine warms up at idle. Checked with manual gauge. Running 5w30 full synth high mileage Mobil 1 . Running down the road it climbs to 20psi. Stomping on it goes to 50 to 70 psi . I have no leaks and I am loosing about a quart of oil between oil changes. A couple of people are saying to change to 10 w 40 . I live in Fla. hot most of the time. Would that hurt the motor? I posted this once before and only one recommended to do that. I am needing more feed back on that. thank y'all.

 

Why bother? You've ignored the specific instructions given so far to properly evaluate the system....

 

The old guideline I remember is that an engine needs 10psi oil pressure for each 1,000 rpm.