That is the procedure I normally follow.
Sean

> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]On Behalf
> Of David Brodbeck
> Sent: Wednesday, January 21, 2004 2:08 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: 1981 Westy gas tank capacity
> 
> 
> On Wed, 21 Jan 2004, Karl Ploessl wrote:
> 
> > Sean asked:
> >
> > What is the capacity of a 81 Westy (stock).
> > My gas gauge does not work and I think my mpg just dropped 
> from 17 to
> > 14 after a tune up.
> > --------------------------------------
> >
> > according to the "vanagon specifications" (for 1981) the 
> fuel tank holds
> > 15.9 (US) gallons (60 liters)
> 
> However, if you need the tank capacity to do mpg calculations, you're
> probably doing them wrong.  Here's what you want to do:
> 
> - Fill the tank completely.  Reset your trip odometer.
> - Drive a couple hundred miles.
> - Fill the tank again, at the same pump if possible.  Use the same
>   procedure.  (i.e., if you stopped at the first shutoff the first
>   time, stop there again.)
> - Note how many gallons you added.  This is how many you used since
>   the last fill-up.  Divide the reading on the trip odometer by
>   this number.
> 
> The pump shut-off is not always consistent, so it's best to 
> do this a few
> times and average the results.  On a car that I've just 
> bought, or that
> I'm planning on doing engine work on, I'll often actually 
> keep a running
> log of the fuel economy for every tank of gas I buy.  This 
> can be really
> educational about your driving style and the effects of any 
> repairs you
> do, as well as giving you an idea about your engine's 
> relative state of
> tune.  A small notebook is excellent for this, or if you 
> carry a PDA there
> are free software packages that will do the job for you.
> 
> 
> David Brodbeck, N8SRE
> '82 Volkswagen Diesel Westfalia
> '86 Volvo 240DL wagon
>