What year truck and what weight of oil? FWIW, out of the 3 weights of oil I've run over the years (15/40, 5/40 & 10/30), the 5W40 always had the lowest oil pressure (<30 psi) when hot. The problem with pressure below 30 psi is the piston cooling oil "squirters" which cool the bottom of the piston operate at 29 psi.oil pressure drops to 22 lbs @ 210 degrees, and 5 lbs @ an idle, when towing my 5th wheel 12,500 lbs weight
HH,I run 5w40 full syn 9000, specifically because it holds psi at higher temps (280+) and doesn't thin out. Never drops below 45 @1800r.
Is this a new problem while running the same type of oil?
What did it do in the past?
Or did you just notice the psi at higher ECTs?
Wasn't that running non coolant cooled turbo(s)?...the 5w40 had lower oil pressure when hot but "flow" when cold is a benefit in cold weather.