evanis300

Living in Florida where the weather is hot, does it make a difference whether I put synthetic 5w/30 or 10w/30 in my 2002 is300 with 70,000 miles?

jellyd

you will need to stay with 5w-30, since you asked let me tell you why. anytime you decide not to go buy what the manufacture states you better know what you are doing, all the R&D guys @ toyota know what they are doing and they get paid big to do so. the first # on the weight of oil is the THICKNESS when its cold, so either oil (you are choosing from) has the same thickness when the car is warmed up. 90-95% of all wear and tear on an engine is within the first 10 min of driving, going to a thicker oil while cold will only cause further damage and struggle on the engine. do you're own research about oil here http://www.bobistheoilguy.com/forums/ubbthreads.php