Can anyone tell me what the normal oil pressure should be? I have fitted an aftermarket guage and it reads 30psi on tickover when warm but goes to 100psi when reved to about 4k and above which is as high as it will read. The reason for asking is that I have an oil leak from what appears to be the rear crank oil seal which I replaced when carrying out a manual conversion not many miles ago. If the car is left ticking over, it doesnt leak however when I drive it or rev it high, the rear crank seal leaks. The oil then goes all over the gearbox, exhaust etc. Is 100psi normal as I dont want to go through replacing the rear oil seal again if it wont cure the problem? Any help apreciated. Car is a 1989 twin turbo.