oil temp

[bobcowan]

60*C = 140*F.

If you have a good oil cooler in cold weather, this is common.

without a cooler, Oil temp will usually be sorta close to water temp. Oil is heated predominantly by RPM's. In street use, your oil will never be hot enough to need a cooler. Even with a thermostat, you could have a tough time getting the oil warm enough to work well.

People think you need to get the oil temp above 100*C to boil off the water. That just isn't true; if it was your kitchen floor would never be dry. Water will evaporate at most any temp above freezing.

But, oil does have an operating range. Oil companies keep that number close to the vest, as I have never been able to find anything specific. Above 180*F seems to be a common consensus. But racers like to see it above 200*F or so.

Studies done on military vehicles in Alaska showed that oil temps below 160*F will cause increased cylinder wall wear.

I would not recommend a 15W oil. Too thick when cold to really lube the engine well in that first 60 seconds or so; where most engine wear occurs. I would change to a 0W or 5W.