Back from the dead
Anyways, I was looking through my owners manual last night and found this little tidbit of information.
From page #11-14
-Recommended grade and viscostiy under severe driving conditions.
If the vehicle is used in desert areas with very high temperatures, or used for heavy-duty applications such as towing a trailer, use of oil with the following grade and viscosities is recommended.
API classification SL or SJ or SH:
SAE viscosity No.: 30, 40, 10W-50, 20W-40, 20W-50