B6 1.8T Petrol/Fuel Smell

[Skezza]

Morning,

I picked up a reasonably cheap MOT'd for 12 months 1.8T in Denim Blue a few weeks ago. I am pretty chuffed to bits with it, but as usual with a cheap second hander, just fixing the odd gremlin. All my electrical woes are sorted (remote central working now etc etc).

However, one thing that's been nagging me. I'm convinced there's a small (but noticeable) fuel leak, and I'm trying to track it down. I'm hoping you guys might know the most likely locations based on my description.

So, when I enter the car in the morning after I've left it all night. You can smell it, and you can smell it after I've left it at work for a day. When driving, it does tend to disappear, even when stopped. However, when driving with the sunroof open, it's incredibly strong to the point you really have to close the sunroof, especially when cruising at say 40mph in 5th. Passenger window down, I couldn't smell it, driver side window, you can, but not as strong as the sunroof.

When the car is stopped and I am walking around I'll occasionally get a whiff and it's usually when I'm walking down the drivers side.

So far, I've considered the fact it's possibly the fuel filter, perhaps it's not been installed properly. Any other suggestions?

Please don't ignore if you have ANY advice

[Alan02]

Definitely check filter and lines along o/s floor, but as you can smell it while driving also check under bonnet area. Another is the charcoal filter control under the drivers wheel arch liner, it vents tank fumes back into engine.

[Skezza]

Definitely check filter and lines along o/s floor, but as you can smell it while driving also check under bonnet area. Another is the charcoal filter control under the drivers wheel arch liner, it vents tank fumes back into engine.

Thanks for this advice. I'm hoping to get it up in the air in the next few days and that may give me a better chance. I assume the easiest way to track it down is with smell? A tiny split could be like finding a needle in a haystack right?

Regarding checking under the bonnet, what's the best way? Someone sit in revving while I have my head under the bonnet?

[fourringsrus]

With the engine not running , stick the ignition on and hope that the pump will pressure up the lines and then look for wet areas on the pipes from tank to engine bay.
I dont much care for the idea of sticking your head under the bonnet whilst somebody revs the engine, you could potentially have a spray of fuel onto a hot manifold and mess everybody up

[Skezza]

With the engine not running , stick the ignition on and hope that the pump will pressure up the lines and then look for wet areas on the pipes from tank to engine bay.
I dont much care for the idea of sticking your head under the bonnet whilst somebody revs the engine, you could potentially have a spray of fuel onto a hot manifold and mess everybody up

What's the easiest way to access the pipes running down the sill?

[Skezza]

Tracked down the smell pretty quickly. Under the rear offside there is a patch, which was wet after I drove it for a bit. Sure enough, I ran my finger across and it was pure petrol. I'm guessing it's a fuel line that has rotten or something.

What's the easiest way to access the pipes behind there, as currently it's covered by some plastic undertray. Does that just unscrew off?

[niall campbell]

Yeah take the tray off and see what the problem is.

[Skezza]

Yeah take the tray off and see what the problem is.

Cheers Niall.

If I remove the undertray now, can I run without it while i fix the issue. I can see it taking longer than a few days. If it's a leak it might need a whole new line (bad bad bad) although I've seen someone selling fuse tape online which claims to fuse to the pipe to make a watersight seal. So very tempting considering it's £15 a roll!

[niall campbell]

forget the fuse tape idea Skezza , not good and wont last. Its your life and passengers that are at risk

It could be an overflow pipe that's choked up causing it to go down a breather pipe or anything

The undertray is either got plastic nuts to protect the threads for the bolts or push on clips, which are reusable

Can you lift the rear seat to have a look ?

[Skezza]

forget the fuse tape idea Skezza , not good and wont last. Its your life and passengers that are at risk

It could be an overflow pipe that's choked up causing it to go down a breather pipe or anything

The undertray is either got plastic nuts to protect the threads for the bolts or push on clips, which are reusable

Can you lift the rear seat to have a look ?

I'm going to get the undertray off now, try and have a better look. Quite worried about this though. I really hope it is an overflow as you say.

Sure, I can lift the rear seat. Just remove that plastic lid isn't it then I can access the tank? I assume that is where the smell is leaking into the car anyway.

Shame about the fuse tapes not working, a new fuel line though could be a seriously big job on this car and there's literally no details about