Date:         Tue, 21 Apr 2009 11:56:27 -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
In-Reply-To:  <c2c43a7e0904210757m44b3371cn2e5d12cc753ae500@mail.gmail.com>
Content-Type: text/plain; charset="us-ascii"

> So, does the OEM tank have an 11 mm  outlet?
>  If it's a 7 mm, then it seems to me the issues might
> not be so much tank-related


The OEM tank was 7 mm until mid 1990 production, then it was 11 mm. The
reason is that during the course of Vanagon production VW phased out the
pre-pump fuel filter, which had a 7 mm inlet and 11 mm outlet. As VW stopped
providing the inline filter they simply replaced it with a 7-to-11-mm
adapter. Only near the end of production did they finally change the outlet
size on the tank itself to 11 mm, thereby eliminating the need for the
inline adapter. So a small percentage of late-production Vanagons had 11 mm
outlet tanks, but the rest (as well as all fuel injected Buses) had 7 mm
outlet tanks.

Personally I think the 7 mm vs. 11 mm issue on the Samba is a red herring.
Virtually every VW van made from 1975 to 1990 had a 7 mm outlet tank and the
same fuel pump. If that design caused fuel pump cavitation, we'd all be
experiencing it, not just a couple of people on a Samba thread. My best
guess is the few but vocal people on that thread had some sort of fuel
delivery issue that they failed to correctly identify. Perhaps increasing
flow by going to an 11 mm outlet tank compensated for the actual problem and
thereby resolved it for them. Or perhaps when they switched to a new tank
they also replaced other parts, cleaned things out, etc., and this (not the
increase in outlet size) resolved their problem.

If you believe that using the '90-91 11 mm outlet tank in your earlier
Vanagon might reduce the likelihood of present or future fuel pump
cavitation, by all means order that version of the tank (we sell both).
While I can't say I'd personally bother doing so, I also don't see any
downside besides having to replace some other parts to make it work. You
will need to replace the fuel line from the tank to the pump and eliminate
the pre-pump filter if you have one (or find a different filter at a FLAPS
that has an 11 mm inlet). If you have a 1980-83 Vanagon it's a bit more
complicated because you will have to replace some of the filler parts as
well.  If you have a late 1990 thru 1991 Vanagon which already has a 11 mm
outlet tank, you might as well go with another 11 mm tank.

As for the tanks themselves, there is actually only one factory making the
aftermarket replacement tanks, despite the fact that they are labeled under
various brand names and even countries of origin.  There are thousands of
them in use without any problems. I've been selling them for about 12 years
myself and woudn't hesitate to put one in my own Vanagon.

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

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