Read this thread with interest - but have an alternate question. What about Mobil1 5-40? When I bought my 05 xfire in 06, 0-40 was a pretty unusual oil. Many years later, it is fairly common, up to an including the moniker "European Blend". Today we have a slight tweak on the mixutre, ie, 5-40. As I live in the south, where it does get warm, my thoughts are would this be a better oil? After all, the 0 part of the number is for cold starts and coming from Germany, they have COLD starts. Down here, not so much.

So, would the slightly higher 5 vs 0 be a negative or a positive? My thoughts are that 5-40 oils were not readily available at the time the XFire was sold?

I've been using Mobil1 0-40 since I bought the car. One kicker,that got me to thinking about changing is that the Mobil1 5-40 is MUCH cheaper than the Mobil1 0-40.

What say the collective?
Henry