1. What kind of vehicle you have: 09 Altima 2.5S
2. What your owner's manual says -- not just viscosity, but certifications (look for acronyms like API SM, ILSAC GF-4, etc.) and change intervals as well: API - SAE 5w-30 - change interval: 3750
3. Where you live: Dallas, TX
4. How you drive...