Newell Gurus

Returning from our trip West we ran through some pretty cold weather most of the way. Temperatures in the 20's and in the 30's if we were lucky.

Running down the highway with engine temps just under 200 degrees my oil pressure stayed above 65 psi most of the trip.

Now that we are in slightly warmer Alabama temperatures (50 degrees) I took a test drive - oil pressure stayed in the high fifties.

I am running Rotella T 15w40 motor oil.

I am wondering if oil pressures that high are normal in that cold of weather. 

I can imagine all that oil in the oil pan never gets too warm. Wish I had thought to take a temperature reading of the oil pan with the temp gun but I didn't.

Every engine that I've owned that had a real oil pressure gauge would have the oil pressure drop as the engine warmed up. And, all those engines ran slightly higher pressure in cold weather than warm, even though the coolant temp read the same. We could get into all the complexities of thermodynamics and produce a tome of epic proportions that would both bore you and put you to sleep, but the simplistic explanation is that the colder the weather the easier it is for the engine to rid itself of waste heat in ways that produce slightly cooler and thicker oil. If the weather and the engine get cold enough the oil cooler, which exchanges heat with the engine coolant, becomes an oil heater.