Fuel Vent Pipes
Moderator: martauto
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Craggy73
- E30 Zone Newbie

- Posts: 177
- Joined: Wed Dec 26, 2012 11:00 pm
- Location: Cheshire, UK
Having spent the day doing some repairs to the o/s rear inner arch. I had to cut away all the metal around the neck of the fuel vent pipe opening in the arch. I accidentally cut into the 3 pipes that come up through that hole and around the back of the strut, so I've cut them back inside the boot and taped them up. I assume it's safe to drive with them like that if they are just venting? I'm only ever filling my tank up to half way max at the moment so wouldn't expect the expansion system to be needed. Has anybody simplified the expansion system on the facelift models? If I replace these vent pipes I'm going to re-route them through the boot to the back end of the inner arch and pop out there.

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penton08
- E30 Zone Camper

- Posts: 1206
- Joined: Sat May 10, 2008 11:00 pm
They are not just an expansion tank! It's more of a breather system, the main fuel tank needs to let air in as fuel is sucked out or it will collapse. You might also have issues when trying to fill the tank.
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Kedge
- Old Skooler

- Posts: 7698
- Joined: Thu Jan 13, 2005 11:00 pm
- Location: Leicestershire
With the pipes blocked it'll make it impossible to fill the tank to a decent level.
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Craggy73
- E30 Zone Newbie

- Posts: 177
- Joined: Wed Dec 26, 2012 11:00 pm
- Location: Cheshire, UK
Arh, yes. The large hose loops back to the neck of the fuel fill pipe for air displacement when filling the tank. Will get one of those for starters.

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Brianmoooore
- E30 Zone Team Member

- Posts: 49360
- Joined: Mon Jan 10, 2005 11:00 pm
One of the small pipes is the ONLY way air gets into the tank to replace fuel that is used, so must not be blocked.
The other small pipe and the large pipe are empty of fuel when the car is stopped and on level ground, but can fill with fuel when on the move.
Re routing the pipes through the boot is not a good idea for safety reasons.
The other small pipe and the large pipe are empty of fuel when the car is stopped and on level ground, but can fill with fuel when on the move.
Re routing the pipes through the boot is not a good idea for safety reasons.

