Let’s explain all of those confusing numbers, letters and terms to help you choose the right oil for your car.

But what exactly do those codes mean, and, in particular, what does the "W" stand for in engine oil? When it comes to understanding these codes, the "W" part is perhaps the easiest to remember.

Synthetic oil used to be something only performance cars needed, but not anymore. Now it’s the manufacturer-recommended engine lubricant in many mainstream vehicles, such as the Subaru Forester ...