This may not apply and I have no proof of this but on a then near new
tank etc and canister filter post pump, with, without that square pre
pump filter pump, pump made (makes) same amount of intermittent pump
noise. Some time ago, I discovered a failed seal at an expansion tank.
This allowed dirt into expansion tank and may've allowed a bit to get
into tank although those hoses from expansion tank to fuel tank are
only ~ 1/4" ID.

My aftermarket tank, and new on the shelf tank for later model, do not
have an internal screen (unless it's hidden under plate at bottom of
tank where pick up tube connects).

On one trip, while climbing a long steep hill on a hot day, the pump
was VERY noisy. When pulled over at top of climb, engine idling, it
stalled. I suspect poor tank ventilation as cause. The "whoosh" sound
of air rushing into fuel tank once cap was removed was a clue. Engine
started right up after that.

Neil.

On 4/4/21, Dan N <dn92610@gmail.com> wrote:

> I wonder if there's any benefit or or problem if I put another canister
> fuel filter (same as the one downstream) upstream of the fuel pump?
>
> I was thinking of a smaller one but then a smaller maybe too restrictive?
>
> thanks
>
> On Sun, Apr 4, 2021 at 11:27 AM Richard Koerner <rjkinpb@sbcglobal.net>
> wrote:
>
>>  I had this issue once; whining fuel pump.  Horrible performance at
>> higher
>> elevations and higher ambient temperatures.  Totally ruined a Colorado
>> trip
>> in summer.  Dennis H. immediately diagnosed.  Replaced fuel tank.  All
>> good.
>> But.....now just spitballing here, pure conjecture....what about removing
>> screen on outlet of fuel tank and adding a pre-fuel-pump filter?  Why did
>> VW put this screen into Fuel Tank?  I guess they never thought these
>> bricks
>> would be running over 30+ years.

-- 
Neil n

VE7TBN

1988 Westy 50º ABA swap: https://tinyurl.com/yap5hpwt

1981 Westy 15º ABA swap: https://tinyurl.com/y9n4xob8

VAG Gas Engine Swap Group <http://tinyurl.com/khalbay>