I know 25 psi is ok for idle. My question is; Is the oil pressure drop from cold at 70 psi, to hot 25 psi going to be ok? It used to be about 10-15 psi higher a few years ago.
It goes up to about 80 when cold, and stays up there when I'm driving.
That could be normal, kind of depends on what the temp is and what your idle speed is and stuff like that. I've run a lot of engines on the dyno that held 70+ while cold but drop into the 20 range once the oil is hot.
If you really want to know what is going on stop asking questions on the internet and install a temp gauge in your oil pan. Then start taking notes. Write down the temp and the pressure and the engine speed for several different temps and speeds each time you drive the car. Once you have a good idea of how it is behaving then change the oil to a different viscosity and run the tests again. Do that three times and you'll be an expert. Then you can come back on the board and explain what is going on.
