[T3] Gas Leak ? ! ?

[Jim Adney]

Some of you may recall that I recently mentioned that I got only 12 
mi/gal on my last tank of gas. That was so low, that I was seriously 
thinking that my tank had been syphoned, something that hadn't 
happened to me since the gas crisis of 1974. 

I had looked for leaks a few days ago, after noticing the bad 
mileage, and hadn't found any, and a leak of that size should be easy 
to spot by the drips on the driveway. A couple days ago, after 
running some errands, I smelled gas and spotted a small wet spot on 
the pavement under the gas tank. This morning I checked again, after 
letting the car sit overnight; there was no wet spot.

Then I started the engine and looked again. Soon there was a drip a 
second coming from under the gas tank.

This afternoon, I had some free time and decided to find and fix the 
leak. I put the front end up on jack stands and then ran the pump 
using some small clip leads, but when I got back under the car, there 
was no leak to be found. Even wiggling the hoses revealed nothing.

In the end, I decided that the problem must be that it had been quite 
cold last week, 40-60 F, but today it warmed up quite a bit, to 75 F. 
Rubber hoses shrink a bit when cold, so I'm guessing that this 
allowed one of mine to shrink just enough to leak a bit. I tightened 
up everything under there slightly, especially the 2 ends of the 
single pressurized hose (I've removed the "damper" on this car.) 
since I only saw the leak when the pump was running.

My general practice is to only tighten my hose clamps slightly, to 
avoid damaging the hose, which is easy to do. It looks like they 
needed to be slightly tighter. I'll let you know if this seems to 
have fixed the problem. In the meantime, I filled the tank, getting 
12 mi/gal again, and hope to be back to normal on the next fillup.

BTW, while I was looking around for leak possibilities, I checked my 
replacement overflow hose bits. I was very pleased to find that they 
were all intact and that the hose was still quite flexible and in 
much better shape than an OE part would have been at this age. It's 
been in there for 2 or 3 years and shows no signs of age.

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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