Fuel leak/tank overflow, type 44

Kneale Brownson knotnook at traverse.com
Mon Sep 6 15:51:51 EDT 2004

The filler pipe is connected to the tank with a flexible rubber-like tube
that has hose clamps at each end.  If loose, that could be a source of
leaking in a full tank where expansion from cold fuel stored underground
warming up in hot weather created pressure.

There also is a large O-ring sealing the fuel pump access to the top of the
tank.  If the pump's been replaced and that seal lost or damaged when the
top was reinstalled, the same pressure build could cause leaking.  I'd
expect it to come on both sides of the tank in that instance, though.
There are three Phillips screws in the center of the shelf in the trunk
holding a cover that, when removed, exposes the top of the tank.  You won't
be able to see much, but if this has happened repeatedly, there may be
signs of it.  If you take off that cover and go fill up again in similar
weather circumstances, that might let you see if the leaking is from around
the seal in the top of the tank.

If you take off the protective pan and look up past the rear of the tank in
the (US) passenger side, you can barely see the hose clamp that holds the
flexible connector to the tank.  You have to take that loose and pull out
the filler pipe to see the other end of the connector and its hose clamp.
That, of course, requires removing the fender liner too.

When I replaced my leaking tank on my 200q20v,  I found several spots high
up on the driver side, well above the famous seam, where the tank was
rusted enough that it would have leaked from there soon too.  The S-car
tank I got to replace the rusting one had no rust on it, and I sprayed it
with several coats of one of those anit-rust gravelguard paints.  Hoping to
not have a fuel tank leak with that car ever again.

At 08:47 PM 9/6/2004 +0200, Eyvind Spangen wrote:
>A few days ago, I bought an '89 100Q (NF engine). Today, I filled about 68
>litres, a full tank.
>I drove off, a few miles, then parked the car and noticed a real fuel smell.
>Looked under the car, and the part of the fuel tank by the right rear wheel
>was wet with fuel, some of it was dripping off the protection cover under
>the tank too.
>It did not come from the fuel tank seam, it almost looks like it's running
>down from the top of the tank. No huge leak as I couldn't see any spill on
>the ground except some drops, but the fuel smell was awful, it would even
>come into the car if I opened a window while driving. In addition, with
>$1.30/litre, I can't afford spilling any fuel at all.. :)
>Later today, I drove 50 miles, now everything is fine and dry, no fuel smell
>either. I pulled the cover in the trunk to check for leaks, but I didn't see
>anything at all.
>What can this be? Was it the overflow dumping some fuel due to expanding,
>malfunctioning overflow, or is the tank or any of its connections leaking?
>I tried searching the archives, but didn't find anything about type 44 fuel
>tanks except leaking in the seam..
>E. Spangen
>quattro mailing list
>quattro at audifans.com

More information about the quattro mailing list