Does the W in Oil Mean Weight

This is a super common question when looking at motor oil labels like 5W-30 or 10W-40. So let’s clear it up: No, the “W” in oil does not stand for “weight.”It actually stands for “winter.” That’s right—“W” = Winter, not weight. So, What Does the “W” Really Mean? In oil grades like 5W-30, the number…