Hi Mustachians!
I have a 2001 Civic LX that's due for an oil change. I last changed the oil about 10,000 miles ago (this was two years ago, with fully-synthetic 5W-30 oil, and those miles are almost all highway miles).
The oil cap on the engine says to use 5W-30 oil, but the manual says to use 5W-20. (Maybe the engine oil cap got switched at some point?) Is there a big difference? Am I harming the engine if I use 5W-30 for an extended period? Or is this a really pedantic question?