[JFP in PA]

Originally Posted by Bob O

I'm also currently using Castrol 5W40 (in an 01 base with 65K on it). I change somewhere between every 5000 and 7500 miles and take it to the track several times a year.

JFP....Would you recommend year round Castrol 10w40 for a car that gets regularly driven in the winter in temps sometimes below O deg F (excluding this last mild winter). Based on your recommendation above my next change (next month) will probably be Castrol 10w40, so I'm curious if I should continue to use it during the winter or go to the 5w40 for the cold weather.

Thanks

Bob

We use 10W-40 year round, and it gets plenty cold here in PA in the winter. If you go to Castrol's website, their tech specs for the 5W and 10W oils are not all that different in the cold; so unless you are going to see sustained -25F (or worse), I wouldn't worry about it.