Oil pressure?

[Fred 86 GN]

Seems that my GN engine has lower oil pressure recently...

Used to be:
Hot Idle = 15psi
Cold Idle (30F) = 90psi

Now:
Hot idle = 10psi
At 1950rpm on the highway = 20psi

Does GNttype.org state that it should be 37psi at 2500rpm?

If so, seems mine is a bit low. What could change in the engine to lower the oil pressure?

Is it recommended to run thicker oils to raise the pressure?

The car seems to run good still.

Thanks,

 

[Steve Wood]

I think 37 was the factory spec.

Any sudden change in normal oil pressure is probably a cause of concern, in my opinion. Might be time to find out if there is any metal in the oil or, if you have the original timing gear, a coating of nylon on the oil pick up. Another possiblility would be a stuck open bypass valve in the cover that is bleeding off oil.

It gets worse from there. Bad bearings, etc.