anyone ever changed a vent pipe??

[tobias]

the one that runs from ns engine bay to rear richt wheel arch

regards toby

[smithy318i]

yes.

it goes to the fuel tank breather iirc

[Treeman612]

This pipe goes from expansion tank to n/s of engine bay. All it does, as far as I can tell, is allow air from expansion tank to escape, but why it is routed all the way to the engine bay, I don't know? See my post on changing fuel tank - warning, cos I mixed up the fuel return and this breather where they plumb in above the fuel filter1 - result all the returned fuel filled up the expansion tank and pi**ed out of the breather at a rate of about 15 litres a minute

[tobias]

hey treeman

in your opinion did the tank have to be taken out to change the vent pipe???

[Martinaston]

Some engines have a canister that vents into the throttle body to help start the engine.
The pipe is in 2 or 3 pieces along the car and the bit running along the top of the fuel tank is a plastic pipe so should be ok. Its the bit running along the floor pan that rusts or gets damaged, you should find a few jubilee clips and possibly a fuel filter on the front nearside of the tank.

[tobias]

yes thats the one but piple goes up side of tank cant see where and if i can i wanna avoid taking the exhaust prop and then tank off

[Martinaston]

So why does it need changing ?

[tobias]

bought m3 from suthhampton couple of months ago. brought it to the isle of man. over here we have no mot but we have a manx road test which is lke the mot but more rigarus. anyway they failed it on this. its corroded at the bend where it goes up behind fuel tank. so to get it manx registered and on my new plates (mn 2300) i need to replace this pipe. its arriving tomoz and being replaced on sat. but as i say i dont wanna have to take all the bits off if i dont have to

[Martinaston]

I'm not quite sure how they can see the pipe above the fuel tank to see its rusted
You could just drop it slightly so it rests on the prop and then get to the clips through the access panels below the seat, all three pipes are clipped together in a couple of places.
If you remove the one above the pump you should find a join with a crimp going to rear piece that goes to the expansion tank. From under the car you should find another join where it connects to the steel pipe that runs to the front, but that is normaly under the tank not above it
Are you sure there not mixing up the vent pipe with the feed line ?

[tobias]

its the steel pipe that runs from carbon filter in engine. runs down ns of car and when gets to tank goes up the side of it. its rusted on the 90 degree bend wher it goes up behind tank. i.e you can see it from underneath

[Martinaston]

There should be a join just there otherwise the tank and pipe would have to be fitted/removed as one piece, which would be a pain

[tobias]

ithink it goes part way up side of tank and joins a rubber hose but bcant see

[Treeman612]

Hi, Tobias - no, you don't need to drop the tank to change the vent pipe - I was just burbling about my c*ock up connecting pipes the wrong way round. If your set up is like mine, changing the corroded metal pie should be easy(ish!). The vent pipe only goes up around 75mm at the back before it is joined with a clip to the plastic pipe running over the fuel tank. If you remove the plastic strip along the left side front of the fuel tank (2 x 10mm plastic nuts + 1 x phillips screw, you will access the fuel filter. De-pressurise fuel system, undo jubille clip holding filter and either disconnect feed + supply pipes and remove altogether (probably worth changing it while you're there, only a few quid from Halfrauds) or just pull it gently out of the way, and you will see where the vent pipe joins the plastic pipe. Undo plastic pipe here, do same at engine bay end, and the corroded steel pipe just unclips from under the body.

[tobias]

thanks treeman.

gonna be replacing fuels lines also thought i may aswell with all the f**king around i will be doin anyway thanks for your help

[tobias]

will have a better idea tomoz when new vent pipe arrives

[tobias]

thanks again for everyone that left info for me

[Brianmoooore]

Some engines have a canister that vents into the throttle body to help start the engine.
.

Nothing to do with starting the engine. It's emissions equipment to prevent fuel vapour being released into the atmosphere.