I was driving the other day in very hot weather here and noticed that my oil pressure gauge was reading right at the end of the red zone (although the idiot lights were not on). I checked my oil level at the next stop, though, and it was at normal max. level on the dipstick. I’m curious as to how the increments shown on the oil pressure gauge (face lift 4.0s) relate to actual PSI. I have heard that standard “acceptable” for oil pressure in all cars is 10 PSI per 1,000 RPMs of engine speed.
Later that night, when temps had dropped outside considerably, my gauge read in the usual range once again. All I can think is that perhaps it’s getting time to change my pressure sender unit (?) With very hot weather (and hot/thinned oil - I’ve been running 10-30 generic synthetic) it inaccurately reads low, perhaps (btw, this is the “true”, OEM type of sender)? Superblue has almost 90K miles on her now, so maybe that’s due … (?) The only other possibility I can think of is that maybe the PO had disconnected/bypassed the oil cooler system for some reason.