Oil pressure low once warmed up around 16 - 18 psi ???

[Almadean]

have a 14 chevy silverado 5.3 LT got code p066d for oil pressure selonid off was told it was my oil pump, well after a 20 hours job i change my oil pump, oil pressure sensor, timing chain and gears added all new filter and oil. started truck up code went away but now my oil pressure is low again. at cold start 40-50 psi and warm 30 psi, once she gets to 210 and drive it when i come to a stop or at idle shes at 16-19 psi i now this is TO LOW for chevy it states atleast 22 psi which i dont have. What could this be? i aslo change the screen in the pressure sensor too so what could be left. NO noise at at not tick everthing else is fine. I did my lifters in 2022.

[Grumpy Bear]

Do a 'test block' pressure test. Don't rely on the dash gauge. Start there and see where you land. Here are your targets. Compare to the dash for reference but don't rely on it. 

 

Hot oil pressure minimums.

22 psi @ 1,000 rpm

30 psi @ 2,000 rpm

33 psi @ 3,000 rpm

LV1, LV3, L83, L86 and L96.

[Almadean]

We placed a manual Guage on it and at cold start she's 40 to 50 and warm she's at 30 at temp 210 at idle she's 16-18 that's where it's to low. After she warms up it has gotten as low at 10. 

[Almadean]

Gm states at warm idle the lowest she can be is 22 psi I'm at 10 to 18 at warm temp 210.

[Almadean]

The dash Guage matches my manual Guage 

[mjm-1957]

How many miles are on this truck? Is the bearing clearance too large from wear? Connecting rod side clearance too large,cam bearings worn out?

Edited June 19, 2024 by mjm-1957

[Almadean]

188 thousand miles had the lifter done last year and they stated no issuse with bearing or cam... 

[Almadean]

If those things happen why would they happen over night?

[Almadean]

Wouldn't my engine make a noise if those things went up? 

[Grumpy Bear]

52 minutes ago, Almadean said:

Gm states at warm idle the lowest she can be is 22 psi I'm at 10 to 18 at warm temp 210.

 

What I posted if from @newdude, a GM tech, a few years ago. No mention I can find of a minimum pressure at idle. But 10 psi per thousand is a normal benchmark. Lowest test pressure is at 1K rpm. Why? Because 22 psi is the minimum required to latch the AFM lifters and that can never happen at idle. About 1200 rpm is the lowest the AFM even tries to work. IF you can hit those test pressures at those rpms at full temp your idle pressure is fine. 

[rlcole321]

may have an issue with the VLOM (valley lifter oil manifold), that's where the oil goes to control the AFM, also does this L83 have a vane type oil pump or gear type? (gear type requires alignment). Anyway, I did a AFM/DOD delete on my L83 and modified the VLOM by removing the oil solenoids and forgot to (actually didn't realize) plug the oil galley going to the oil solenoids which'd caused low oil pressure at temp., but after I plugged the port then oil press. was good. So check that for leaks or oil drainage.

[Almadean]

Thank you i will check

[Cole Shannon]

Hey man did you ever figure this out? My truck is doing the same thing… low oil pressure at idle after engine reaches temp, 10 psi on the gauge. I replaced the oil pressure sensor and filter screen too…