I realize they recommend 0w40, but I have 5w30. I live in So CA where the weather is moderate so I wanted to know if the 5w30 is ok. If someone has a technical explanation of why one is better than the other, that would help a lot.

Thanks

 

From the manual:

generally above –13°F/–25°C SAE 0W-40, 5W-40, 5W-50

generally below –13°F/–25°C SAE 0W-40 approved by Porsche

I use 0W-40 since most wear occurs on startup and the less viscous oil flows more easily cold.

 

Anything other than 0W40. Minimum 40 weight oils. Preference 5W50 or 15W50.

 

I wouldn't run anything below a w40 in your area.. I personally use 5W-40

SAE Viscosity Grade Motor Oil: 5W-30

Temperature Conditions: Below 0° F
Description: Provides excellent fuel economy and low temperature performance in most late-model automobiles. Especially recommended for new cars.

 

I knew Costco has the 5W-30 for sale, but I ended up returned it and buy the 0W-40 from somewhere else.