Question on oil temperature

[YerDugliness]

Originally Posted by bobcowan

Good operating oil pressure should around 45psi or so. It will drop a bit at idle, but not too much. Too much oil pressure is not necessarily a good thing. The oil should be "thick" enough to maintain proper oil pressure. Whatever viscosity that might be. In the winter, you should run a fairly low winter weight. Since we rarely drive our cars in sub-zero temps, a 15W is probably fine.

20-25psi at hot idle is fine...

I paid particular attention to the coolant temp and oil pressure gauges on a 100+ mile drive yesterday, ambient air temperature about 70*.

Once up to operating temperature (a stable 180* with occasional increases to 190* when I turned off the puller fan), the oil pressure at idle never fell below 30PSI. This drive was in a fairly high-traffic area (I-45 coming into Houston from the north), but it was at a fairly low use time and speeds seldom fell below 60 MPH, most of the time pushing 75-85 MPH. When traveling between 60 and 70 MPH the oil pressure was a steady 55-60 PSI (I think 60 PSI must be the bypass pressure for the oil pump) and the coolant temperature was consistently at 180*. When pushing 80-85 MPH, the pressure fell to about 45-50 PSI when the coolant temperature registered 190* (I had to keep the puller fan off to get it to that range, it never went higher).

Considering the recommendations you made, Bob, it looks like I'm right in the correct pressure range. I would probably run a higher viscosity oil during hotter weather to keep the oil pressure up with the increased coolant temperature that would naturally result from the higher ambient air temperature.

Feeling much better about things now......but, an oil temp gauge is still high on the "Must Have Items" list.

Thanks for the great info!!!

Cheers!

Dugly