If you've ever performed your own oil change at home or even just popped the hood to check your oil level, you may have noticed the mix of numbers and letters emblazoned on your engine oil fill cap or ...

The numbers and letters on a bottle of motor oil can look like gibberish if you aren't sure how to decode them. 5W-30, 10W-40, 0W-20... What's this supposed to be telling you? Does the "W" stand for ...