Date:         Thu, 3 Jun 2010 22:46:36 -0700
Reply-To:     Peter DiFalco <peter.difalco@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Peter DiFalco <peter.difalco@GMAIL.COM>
Subject:      Re: Upstream Fuel Filter dissection results
In-Reply-To:  <AANLkTil9haOYWMlpDeXCtFGM7c2-I4H4WKsT4N7O80Wf@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

As I recently learned on the list when I opined in a similar vein,
insufficient fuel flow to the pump due to an upstream filter, perhaps a
clogged filter, causes cavitation in the pump and may ultimately harm it. So
maybe VW thought it was better that a few things flowed through the pump
than that the pump work so hard to pull fuel through the filter. I'd be
interested to hear how it goes with the extra upstream filter you and Max
have installed.

-Peter

On Thu, Jun 3, 2010 at 10:07 PM, Don Hanson <dhanson928@gmail.com> wrote:

>  I just did my 'maintainence' under the van, too.  I added an inline metal
> filter, from a Triumph MC actually, between the tank and the pump inlet
> because I had it and because the fuel pumps are costly to replace and the
> filter isn't...I think maybe $15 or so...probably much cheaper if it didn't
> say "Triumph" on it...  I didn't cut open my bosch filter but I did put
> about 120 psi of air into the outlet and blow it onto a white paper
> towel....no chunks no grit came out.
>  I checked all my one year old fuel line and it looked perfect still.  I
> didn't replace my (jetta 1.8l inline) fuel rail with the metal one I have
> waiting, yet.
>  I dunno why VW put the filter down stream of the fuel pump in the first
> place...but I bet someone will tell us.
>
>  Don Hanson
>
> On Thu, Jun 3, 2010 at 7:08 PM, Max Wellhouse <dimwittedmoose@cfu.net
> >wrote:
>
> > I've been using a 1/2" gas valve shutoff upstream of my upstream fuel
> > filter for several years now to make th upstream and downstream
> > filter changing a little less of a hassle.  It also makes a decent
> > cheapy theft deterrent if you park in nasty neighborhoods.
> >
> > Last night I pulled the upstream filter and the downstream filter for
> > annual replacement and decided to see what they had caught in a year's
> > time.
> >
> > The downstream filter was made in Poland and I think I bought it at
> > an AutoZone or Advanced Auto, so I doubt that it was a Bosch.  It had
> > an aluminum housing as opposed to steel.  It had it's share of dark
> > colored stuff, but no chunks of rusty gas tank or anything like that
> > further supporting my theory that an upstream filter  is the best
> > protection you can give your fuel pump other than keeping from
> > running the tank dry trying to make the next gas station.
> >
> > Since my 90 GL: didn't have an upstream filter in it to begin with, I
> > put a metal in line filter from WIX in there that had male 1/2" barbs
> > on each end.  Current part number is 33248. There's a 5 in front of
> > those 5 numbers, but the local parts guy told me that the first
> > number simply denotes where the filter was made. They make a plastic
> > one too in the same configuration, but I don't have that number
> > handy. Paid like $11 for the metal one and the replacement Bosch
> > filter for the downstream side is likely the spare I got from Bus
> > Depot some time ago.
> >
> > Cut the Wix apart first as my 2 wheeled pipe cutter jaws were just
> > slightly too small to open it up that way.  I unfolded the filter
> > media and to my surprise there were no rusty chunks of gas tank in
> > there.  What was curious though, was all the dried grit stuck to the
> > circumference of the inner metal walls.  Sure glad all that didn't go
> > through my fuel pump.
> >
> > Those contemplating doing this mod, there is plenty of horizontal
> > room for the valve and the Wix filter between the tank and the pump,
> > but I might need to research just how important it is to have
> > unrestricted flow from the tank to the pump as the valve body opening
> > diameter might not be equal to the diamter of the hose, and as the
> > upstream filter clogs up, that could I guess cause stress to the
> > pump.  The van's been getting like 5k a year drive time, so longer
> > driving might need more frequent filter changing.
> >
> > YMMV
> >
> > DM&FS
> >
>