So its time for my first oil change and I live in Southern California you know the place that never snows or freezes and just a few days in the 100's a year and in the engine now is 5w40 according to the sticker on the window.
And I see alot of people say to use 15w40? So should I change or just leave the same and what would be the benefit if any by changing?

 

Rotella 15w-40 is very popular because it is a heavier weight for added protection, in addition to the fact that it is rated for diesel engines and has an abundance cleaning agents. However lots of people also change their oil seasonally to 5w-40(I believe Rotella T6 is the 5w-40 and it is synthetic).

So I would just stick to a 40 weight oil, preferably Rotella or Mobil 1 Delvac, with a mobil 1 301 oil filter. Maybe 15w-40 in your case because it is so hot.

 

I agree with the Rotella, or you can go heavier as I did when I lived there and run a 20/50 along with a good filter like a Mobil 1-301.