Hello, I have a 1989 Chevy K1500. It is a 5.7l with 25k miles, and a factory oil cooler. The truck is losing oil pressure at idle after it warms up. I have replaced the stock oil pump with a high volume unit to no avail. I installed a mechanical guage that reads in 5 psi increments, and the pressure reads between 25 and 50 psi at the various cruising RPMs. 10 psi at 1k rpms, 25 psi at 2k rpms and 45 at 3k rpms, At an idle after driving around it is at most 2 psi usually between 0 and 1. I am using 10w-40 oil and a fram TG3980. Any help is appreciated. Thank you,
Well, If youre truck is idling, Youre gauge isnt going to read the Psi at a noticeable reading, Cause its using a low about of Psi, Now when the gas and RPM's are increased, Then you should see the PSI climb up in pressure, Now if the PSI doesnt increase I would get a little worried, Usually you would have a problem with the oil pressure sending unit, Or oil pump.