I just want to know if 5W-20 oil is applicable to SR motors?... it just came up to my mind, when my friend asked me to change his oil on his brand new civic (DA17) to my surprise this 5W-20 viscosity is so hard to find. The oil flows like water, it's so thin. Does this 5w-20 engine oil requirement got something to do with engine's tighter clearances? any ideas?... thank you