Fuel smell but no visible leak ???

[slobbo]

I am getting a wiff of fuel from the offisde rear wheel arch (near the filler). The smell is only there whilst and for a short time after the van has been running. I have had a good look and can't see a leak anywhere. Anyone suggest where it could be coming from. Their is no evidence of a fuel staining or puddles on the ground. I is a VR6 in the back but I have a feeling this might have something to do with the filler neck but if so why am I only getting the smell when running or just after. I have been underneath just after a run and you can't smell it directly under the engine just from the arch and a trace from the vent. Any ideas?

[peasant]

The diesel has vent pipes that run back up along and into the filler tube, dunno if the petrol has them as well.

Take off the plastic around the filler cap and you should see them (if they're there) ..one of them might need re-connecting

[SYNCROSPARESUK]

the vent pipes connect to the top of the tank with small bore plastic pipes, these can get get brittle over time and break off, you then get vapour and fuel smells but no visible leaks......unless your syncro is upside down....

[slobbo]

Can you get to them without removing anything major?

[syncrosimon]

Slobbo, I replaced all my petrol lines on the syncro for just that reason. Now mine are all new genuine VW hose, and I still get the smell.

There are three pipes that lead out of the petrol tank including the filler pipe on the offside, the filler overflow pipe, and then the smaller vent pipes from the two gravity valves on the top of the tank (these close when upside down) The end of this pipe just ends behind the filler plate, and I think when the petrol tank is being heated by a hot engine and gearbox combo, this vents petrol vapour into the off side intake vent.

I think this was a bit of a shortcut by VW, the American syncros's have an evaporative charcoal cannister attached to that vent pipe which then feeds to the engine, so it shows that vapour comes out of it. They also get a petrol tank heat shield. This smell is particularly annoying when camping, as the petrol smell is worse when you just arrive and get the van set up, and on left hookers the petrol smell is in the awning!!

Simon.

[slobbo]

Thanks Simon. Basically your saying it isn't something to worry about. It is just as you describe. Once I stop the smell is there for a short time then no more and as I have an awning on the offside it fills with the smell. Answer I guess is to not connect the awning up until the engine cools and the smell goes.

[torchy]

Oh the power of a forum! I have this problem and I find this answer from 2.5 years ago! Many Thanks, it's been driving me nuts!!

Slobbo, I replaced all my petrol lines on the syncro for just that reason. Now mine are all new genuine VW hose, and I still get the smell.

There are three pipes that lead out of the petrol tank including the filler pipe on the offside, the filler overflow pipe, and then the smaller vent pipes from the two gravity valves on the top of the tank (these close when upside down) The end of this pipe just ends behind the filler plate, and I think when the petrol tank is being heated by a hot engine and gearbox combo, this vents petrol vapour into the off side intake vent.

I think this was a bit of a shortcut by VW, the American syncros's have an evaporative charcoal cannister attached to that vent pipe which then feeds to the engine, so it shows that vapour comes out of it. They also get a petrol tank heat shield. This smell is particularly annoying when camping, as the petrol smell is worse when you just arrive and get the van set up, and on left hookers the petrol smell is in the awning!!

Simon.