Petrol leak when refueling

[Clifford Pope]

This is an odd leak that has suddenly started without warning.
It occurs only when filling up at a garage, and is a small dribble on the ground from under the front right-hand corner of the tank, ie next to the filler.
It only happens when actually putting in the petrol. Afterwards, even with a full tank, there is no leak, even with the petrol sloshing around in the tank.

There is no leakage at the filler itself, nor at the part of the inlet pipe visible from inside the boot.

I cannot find any trace of leakage from the pipe itself, and the connection to the tank looks fine. I am thinking it must be from the vent pipe or its connection to the tank, but it is impossible to see and access is very limited. I am thinking the leakage must be something to do with petrol bubbling back up this thinner pipe but only when refueling. I have even tried watching underneath while someone pours in petrol from a can, but nothing happens. It is I conclude caused only by the special gush from the garage filler.

How do I get access to the top of the tank/filler connection, or the vent pipe? I presume to lower the tank I need to disconnect the filler pipe, but how do I do that without access?

The car is a 1991 model, so I presume has the later version of filler pipe.

[Bugjam1999]

Mine did the same, with a smell of fuel in the car with a full tank- took me literally years to find the cause.

One rib of the concertina section of the filler pipe had sprung a pinhole leak, I think it was only when it got a bit bigger and petrol stained the dirt around the hole that I could find it.

I cleaned the whole area up and covered it with a covering of fuel safe epoxy resin, tightly squished in using my hands and then with zip ties, which also stopped it falling off due to gravity whilst it was curing. Been absolutely fine since.

The camera position for the photos is pointing up and to the back of the car, through a gap between suspension, exhaust etc. the car was up on a lift which helped a lot.

Cheers

[AndrewBrown]

Seen leaks and fuel smells in 240's a few times in my career as a fuel injection technician and just as Bugjam 1999 says filler pipe flexible tube is almost always the problem every time

I just used to replace the pipe so check that first back in the day for a short pipe it wasn't cheap getting it out is easy....putting it back was a different matter

[Clifford Pope]

Many thanks for that advice. I'd been suspecting the joint between the pipe and the tank, and the vent pipe which passes directly over the point where the leak appeared to be coming from. I'd somehow assumed the convoluted pipe itself was not responsible, but from others' experience that looks likely.

It's impossible to pinpoint the actual point of leakage - it only does it while refilling at the garage. I can't reproduce it at home, and I don't suppose Tesco would let me jack the car up and work underneath while squirting in petrol from the nozzle

I'll try putting filler all round the final inch or so of the pipe.

[Bugjam1999]

I’d probably try tightly wrapping kitchen towel/blue workshop paper around the filler pipe held in place with zip ties, then filling up at the closest petrol station to home, getting back and immediately jacking the car up to have a look.

If the paper is wet that’s obvious, but even if it was wet and dried on the way home, the area where it was wet will look different.

Cheers

[Clifford Pope]

I tried smearing lots of filler all the way round the lowest inch or so of convolutions and also over the part where it joins the tank. it was impossible to tell how effectively I had covered the section at the top where it turns out of view, and impossible I found to get my hand in properly either. I tried using a short wooden spatula as best I could, and then dribbled resin down the back hoping that would cover any areas I had missed.

It appears to have worked - I filled up a few hours ago and there were no drips I could see.

Thank you very much for your tips - I'm so glad not to have to have removed the tank. As a matter of interest, how is the filler tube attached? Mine just has a mass of rust and what might be a kind of jubilee clip. There appears to be no way of getting a screwdriver in there, and no way that it would actually unscrew even if possible.
Anyway, I'll save that problem for another day

[Bugjam1999]

It’s a clamp, but as you say they get so rusty that they’re hard to identify.

Some photos on this page of my project thread for a car I used to own.

Cheers