Vanagon Syncro Gas Leak

[gbrcentral]

Greetings Fellow Forum Members!

I am writing this post in a terminal state of panic, hoping that somewhere in our ranks is the information that will save this project.

My brother and I thought, until a couple pf months ago, that we were successfully completing a 10-year project to re-build a 1987 Syncro Westfalia. All rust removed, all the typically compromised parts replaced, interior refurbished with many of the modern goodies installed. Gas tank removed, refurbished with the kit from Van Café, new straps installed and replaced. All fuel lines replaced with the GoWesty kit. Everything looked like we were ready for Lift-off. The engine is the stock 2.1L; a Factory short block with 25,000 miles on it.

A couple of months ago, on the edge of victory, we came up against a “Houston, we have a problem…” moment. The problem was leakage from several of the new injector hoses. Wrestled with it awhile, and finally ended up ordering and installing new high-end “equal circular pressure” worm drive clamps. That seemed to solve the problem ….. until several weeks ago a new gas leak was noticed that was both severe (a drip per second) and baffling – it had no obvious source. It was not coming from the injector system, and was definitely coming down from the left (driver’s) side of the gas tank underneath the insulation layer, which is of course the area of the fuel level sender. All attempts to pinpoint the source of the leak failed and we started to prepare ourselves mentally for the removal of the tank (%&*#$@!).

THEN THE LEAK STOPPED!

At first we thought that the fuel level had just dropped below the point of the leak in the tank. But we are triple-checking all assumptions by this point, so we poured some fuel into the tank …. no leak. Then we added more, and more, all the way to the full level, and still no leak. All of this was accompanied by various tests – starting the vehicle, running it for various periods of time and driving it for short trips. Still no leak. (It should be mentioned that the shop where it has been garaged for the restoration period is on completely flat land, and the van has not been operated on any sort of a slope for many years.) Because the leak was fairly major, and then stopped spontaneously, it just seems to defy basic logic.

If anybody out there has a solution to this problem (or any general thoughts that would bear on it), we would be eternally grateful!

[MarkWard]

Did you reseal the sender during the renovation? Did you replace the return hose that goes into the sender? Quality clamp?

It's possible you have problem with the fuel vent system causing pressure to build over time causing the leak to come and go. It's really a challenge to put the fuel tank in and not accidentally crimp one of the tank's vent lines that connect to the two roll over valves. Did you check the valves when you had them out to replace the grommets?

You don't want to hear this, but you may end up pulling the tank back down. Well that's worse case. You can reseal the sending unit. I'm not 100 % sold on the replacement stud brackets and viton seals. But often thats all you have available. The tank itself should not have a leak unless someone accidentally drilled into it mounting something in the back of the van. Wouldn't be the first time. Report back when you figure it out. My guess is it did not fix itself. Don't like to screw around with fuel leaks and smells.

[MsTaboo]

Has the tank been out since you took this picture back in 2018?

https://www.thesamba.com/vw/forum/viewtopic.php?t=698252&highlight=

Maybe provide a couple recent pictures of how things look today. General pics of the area and where the fuel is leaking from specifically.

If the Syncro hasn't been driven enough to cause sloshing in the tank then most likely the leak is coming from the fuel return line. Any chance a vent line was mis-routed?
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'90 Syncro Westy 3 knob w/Zetec

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[Nitramrebrab72]

[MsTaboo]

[syncrodoka]

You don't need to remove the tank to service the sender or seals.

[Mikesarge]

[gbrcentral]

Thanks to all for the responses!

The tank was re-installed in 2018 immediately after the picture was taken, and has not been touched since then. The van has been driven maybe a total of 2-3 miles since then at low speeds on flat ground. It resides in an insulated 40x60 machine shed/workshop that does not have huge temperature swings. The shop is located in northern Nevada (not Iowa, where I live) so the temp extremes are not too great, and the leak emerged when the gas tank was less than half full.

We did re-seal the new sender when the tank was re-installed in 2018. I guess there is a chance that roll-over valves could have been damaged during installation, or vent lines could have been mis-routed, but if so, why did 7 years elapse before the problem surfaced?

We will start with the charcoal canister as that seems to have good potential to cause asymmetrical manifestations of trouble. Does anybody know where there is an accurate diagram of the vent line routing? We use the Green Book primarily, combined with internet..

Will try to get some new pics out to you ASAP.

[MarkWard]

Next time it leaks, open the gas cap. See if the drip
Is altered.