Lower oil pressure at startup than when warm?

[Cperk]

Hey guys and gals, I have a 2005 silverado with around 80k miles on it.
Recently I've noticed the oil pressure on cold startup will be just below
40 psi and not increase much with higher rpm. When the engine gets to
operating temp. the pressure goes much higher with higher rpms. I noticed
this about when royal purple changed their formula. Do you think it could
be just an oil press. sending unit going bad or what? Btw, 5.3L and royal purple
5w30 since first oil change with a-c delco filter.

 

[Gabe]

I'm a little confused. The cold oil pressure is 40 psi at idle. What is the hot oil pressure at idle??

Which RP are you using??

 

[xxch4osxx]

I would guess the gauge is on its way out. The stepper motor in the gauge is a common failure component.

 

[GreeCguy]

Originally Posted By: xxch4osxx
I would guess the gauge is on its way out. The stepper motor in the gauge is a common failure component.


My son drives an '05 Chevy truck. Over time, all his guages have gone bad - very erratic - stepper motor on all of them. His started with the RPM guage and progressed to the fuel guage, then the temp, the oil pressure and finally speedometer. Turns out it is a common failing to that model.

 

[TFB1]

Engines won't make higher oil pressure when hot, doesn't happen...