i've noticed lately my oil pressure has been dropping. when engine is cold i have normal pressure, about 58psi and of course comes down when warm. at idle it's about 10-15psi, but lately when cruising, about 3500 rpm it's about 25-28psi. it's never been this low before, seems like it's gotten lower since the temps have risen, been in low 80's recently. the oil pressure does go up with higher rpm's. i'm running royal purple 5w-30 and was just wondering if anyone else has run into this before? i'm not getting and noise from engine or no other noticeable issues. i'm going to pull the lower pan to check clearance to pick-up other than that i'm not sure.

might be time for an oil change... as the oil gets older, it loses viscosity so your oil pressure drops. And the hotter temps are doing it too.

yea i've noticed after an oil change it gets better but i've just never seen it this low before. i've also been thinking about an oil cooler to maybe help.

Shim the oil pump and don't use royal purple.

how do you shim the pump? and why not royal purple?