Do I need to change to a lower weight oil for wintertime? Right now I have Rotella 15w 40 in it. I don't want to have problems when the outdoor temps get below zero.

 

How cold does it get there?

 

There is a chart in the RAVE that shows what viscosity to use based on the temperature ranges.

 

A switch to 5w40 probably wouldn't be a bad idea if it gets below zero.

 

You do not want 5 weight in it if it gets very warm though, it will make lots of racket.

Check the charts.

An occasional dip won't matter much but if you get really low temps for a sustained period then you will need a lower viscosity.

 

It can get below zero on some days. Average is about 10-15 degrees.

 

RAVE says 15w 40 is good to about -10 degrees celsius. Thats about 14 degrees fehrenheit. It might be pushing it....

 

Switch to the 5w-40 for the winter, thats what I do and our temps are about the same as yours, very cold at night but in the upper 20's to low 30's during the day.

 

I agree, you are pushing the limits with the 15/40 oil.

 

5/40 or 10/40......you are coming to the limit of the "15"