Hi. Can someone please tell me what the W in motor oil grades stands for. I think it is winterized and my husband says weight. Who is right, are we both wrong? Answers with links to credible references get meaningless bonus points.
Thanks in advance for your consideration. :eek:
I’ll be damned. I thought your answer was silly until I found out it is basically right. To be picky, it stands for “winter” rather than winterized. Nothing special has to be done to the oil. The W number is the result when they measure viscosity at temperatures that mimic winter,
To clarify, an oil labeled 10W30 meets specs for 10W (measured at -20 degrees C) and for 30 (measured at 100 degrees C). The temperature used for the W rating range from -30 to -5 degrees C, depending on the particular W number. The temperature used for the non-W rating is 100 degrees C for all numbers.
Here’s more than you ever want to know about the subject. Scroll down to the chart and the paragraph below it, they address your question thoroughly.
I came in here all set to move this to Great Debates thinking it meant that George W. Bush was for oil.
I see I was wrong. Carry on.
I was thinking that too. Not the Great debates part, but otherwise.
W is for Walker right? 
What does “WD” mean, as in “WD-40”?
I’ve heard that “WD” stands for “Water Displacing”, and that it was the 40th compound tried for this. The lubricant not only lubricates, it protects the surface from water.
What does “WD” mean, as in “WD-40”?
I’ve heard that “WD” stands for “Water Displacing”, and that it was the 40th compound tried for this.
Keep in mind that WD-40 is a brand name, concocted by a private company. It has no parallel whatsoever with the W designation in motor oils, which is a universally used standard set by the Society of Automotive Engineers.