> Date: Tue, 27 May 1997 07:12:55 -0700
> From: pbailey <pbailey@qnet.com>
> Subject: Re: Oil Pressure
>
> Doesn't 20W50 mean when its cold it will be 20W to help cranking and
> when it's hot it will be 50W or somewhere in between or do I have this
> backwards?....Pat
>
Pat,
I think you have it right. The way I've always had it explained
to me is that a 20W-50 oil will have the same viscosity at start-up
as a straight 20 weight oil, and the same viscosity at higher
temperatures as a straight 50 weight oil. I don't think the numbers
really have any mathematical meaning or units, though. By this, I
mean that if you mixed equal parts 20w-50 and 10w-30, the result
wouldn't be 15w-40 or anything like that. Somebody please jump in if
I'm way off-base here!
Scott
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