I run the series 3000 5w-30 year round in San Antonio, Texas. I use the oil analyzers from Amsoil to check usability for extended drain. Never had a problem with the heat, and the report always comes back "continue to use". I use the double oil filters from Amsoil, one bypass, one full flow. I change full flow filter at 7500 miles and change both at 15,000 miles.
Hawkman54