Originally Posted by dsc
Use whatever weight the manual says to use.
The manual lists many
weights. 5W30 is "preferred" for better fuel economy, but 10W30 and 10W40 are probably listed on the temp. chart for higher temps. It also probably says that oil of a higher viscosity is required to properly lubricate the engine in high temps.
I would not use less than a 10W30 in So. Cal.