What's going on everybody? Since I have ULEV-VTEC, Energy Conserving the oil cap says to use 5W-20. If I chose to use 10W-30 Mobil 1, fully synthetic would it be detrimental to my engine? The car is an Accord 01' LX and it has 38k miles on it, I'm a spirted driver so I like to get the best performance out of the car. What do you guys recommend I do? I was told that it was fine but then I just wanted to double check. So what's the difference between 5W-20 when compared to 10W-30, is 5W-20 thicker so it burns slower or what? Thanks guys.