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From: prophet@umcp-cs.UUCP (Dennis Gibbs)
Newsgroups: net.auto
Subject: The letter "W" in viscosity specifications
Message-ID: <176@umcp-cs.UUCP>
Date: Sun, 30-Sep-84 10:04:55 EDT
Article-I.D.: umcp-cs.176
Posted: Sun Sep 30 10:04:55 1984
Date-Received: Tue, 2-Oct-84 07:34:23 EDT
Distribution: net
Organization: U of Maryland, Computer Science Dept., College Park, MD
Lines: 29


<>

> Here's one for all you auto-netters that have been playing
> with oily questions for the past few weeks:
>
> What does the 'W' stand for in 5W40, 10W30 etc.?  (Maybe Weight?)
>
>                       George M. Verbosh


The 'W' actually stands for 'winter'.  It means what you can expect the oil's
viscosity to be in winter conditions, specifically, at zero degrees F.  If an
oil has a rating of 5W40, then that means the oil should  be  the  equivalent
viscosity of a 5 weight oil at zero degrees F.  There are  also  oils  with a
10W rating, and a 20W rating.  There is no such thing as 30W though,  because
most oils (with the exception of synthetics)  of  weight  30  have  such high
viscosity at 0 degrees F. that it is impossible to measure their viscosity.
I almost forgot, there are also multiviscosity oils  with  a  lower rating of
15W, but these are not very common, except maybe in the trucking industry.

                        Dennis

-- 
Call-Me:   Dennis Gibbs, Univ. of Md. Comp. Sci. Center.
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