Date:         Mon, 17 May 2010 10:09:40 -0400
Reply-To:     The Bus Depot <vanagon@BUSDEPOT.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         The Bus Depot <vanagon@BUSDEPOT.COM>
Subject:      Re: fuel tank outlet vs fuel filter inlet
In-Reply-To:  <AANLkTilmSVSDI1nfU7013OP7vpYmNRRamGbNUlgaOq-2@mail.gmail.com>
Content-Type: text/plain; charset="US-ASCII"

> You are correct in assuming that your van was designed not to
> use that filter. The outlet on your tank is going to be 11mm,
> while the outlet on '80-'84 vans is 7mm. Thus, these earlier vans
> require the prefilter to adapt the size from the 7mm tank outlet to
> the 7mm input on the filter, then an 11mm line from the large end
> of the filter to the input of the fuel pump. Then 7mm all after the
> fuel pump.
>
> Replacement tanks come with 11mm outlets.


That is not entirely correct. Vanagons came with tanks with 7mm outlets all
the way thru mid 1990 (chassis # 24D114613). Only mid-1990 to 1991 Vanagon
tanks had 11mm outlets.  The replacement tanks are available in all three
versions to match the original, and we carry all three.

It is wise to see what you have now before ordering a replacement gas tank,
even if your Vanagon is not a 1990-91, as the tank might have been swapped
at some point and not be original. If you have an '80-85 Vanagon, click on
the tank listings below to learn how to identify whether you have the
correct tank or a 2.1L tank. As for which '86-91 tank you have (7mm or 11mm
outlet), if you have a square plastic filter before the pump (or a 7mm to
11mm plastic adapter in its place), then your tank has a 7mm outlet; if not
it has an 11mm outlet. On an '86-91 you can interchange the two tanks by
replacing the fuel line from the tank to pump with the appropriate diameter
and then either adding or eliminating the plastic filter (depending on which
way you're switching).  Putting an '86-up tank on an earlier Vanagon
involves a bit more work because the filler neck is different as well.

As for the 7mm tank causing fuel pump cavitation problems or noise, that is
not the case. VW vans had a gravity fed 7mm-outlet tank going into the
identical 11mm-inlet fuel pump for 15 straight years (1975 to 1990) without
problems. So that configuration is by far the norm, not the exception.  My
own '87 has it, as did my '89, my '85, and my '77 before that, and I have
never once had a cavitation issue or a loud fuel pump. The 7mm hole in the
bottom of your tank is more than large enough to allow sufficient fuel flow.
If you have a loud fuel pump, you probably have an obscruction somewhere
(dirt, a pinched line, etc.) - or a pump that has been damaged due to a
since-resolved obstruction. The fact that your tank has a 7mm outlet is not
itself the cause of the problem.

Fuel tanks:

80-85 Vanagon:
http://busdepot.com/catalog.jsp?model=43&category=17&group=30

86-91 Vanagon:
http://busdepot.com/catalog.jsp?model=58&category=17&group=30

- Ron Salmon
  The Bus Depot, Inc.
  www.busdepot.com
  (215)  234-VWVW

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