I've looked at the Honda UK oil recommendations for my car (2001 Prelude 2.2L VTEC) and they recommend 10W-40 to be used in this engine. Honda Canada recommends 5W-30 for the same engine. Obviously the bearing clearances are not an issue with 10W-40 otherwise Honda UK would not recommend it. Apart from a slight decrease in fuel economy and power, are there any disadvantages in running 10W-40 (Amsoil 10W-40) in this engine? Would the engine run hotter or cooler with a more viscous oil? I'd only run it in summer here in Toronto, going back to 0W-30 in winter.
Also, is it OK to keep changing oil viscosities? I've heard it's best to choose one oil and stick with it.
Also, is it OK to keep changing oil viscosities? I've heard it's best to choose one oil and stick with it.