gas tank leak

[htown540i]

first time posting, a search returned no results for my problem

97 540i/6
118k miles

Every time I fill the tank, a substantial (~pint) amount of gas leaks out of the tank from somewhere on the far passenger side of the tank. It seems to be coming from the top side of the tank.

I realize this is dangerous and I would like to resolve it myself if possible. If anyone has ever experienced this, please comment. Thanks.

[thejlevie]

Tow possible places for a leak in that location are where the gas filler connects to the tank and where the level sensor mounts. You can see the top of the tank, where the level sensors are once the rear seat is out and cover plates are removed. the gas filler connection can be see with the passenger tire off and the fender liner removed.

[htown540i]

thanks for the reply

The leak is not coming from where the filler connects to the tank, so I will look at where the level sensor is. Is it easy to access once the rear seat is removed? Do I need any new parts to repair the level sensor connection?

[htown540i]

ok I found the leak. after removing the rear seat, I removed the black steel covering to expose the right side fuel level sensor. I filled the gas tank to the top and observed the leak coming from the "vent pipe" connection on the top of the tank. It is a small rubber hose that connects to a plastic elbow fitting which is sealed onto the tank. the diagram is on realoem in the "fuel feed" category. The "vent pipe" connection is not accessible from the hole that exposes the level sensor. It is about 6" away from the edge of the hole, and the clearance is very small. It is also not accessible from underneath the car.

in any other situation, i would cut a hole in the steel to access the vent pipe connection. The reason for not doing that in this case should be obvious.

Does this mean I have to drop my fuel tank to fix this leak? Has anyone ever done that? How difficult is it?

Or maybe I can just leave the problem alone and only fill my tank ~80% every time.

Any help is greatly appreciated, until the problem is resolved I will keep pulling my hair out and living with the humiliating gas odor.

Thanks.

[htown540i]

so no one has ever had this problem before?

[mookish]

so no one has ever had this problem before?I don't think that's a common problem, it depends on how annoying it is to you. Me, I'd just keep the tank below that level until I had the time/money to fix it unless you feel it's a saftey hazard then see what it would take to fix it.

[htown540i]

I got a quote for 6.5 hours of labor...

[htown540i]

I'm going to try to seal the edge of the fitting with rubber sealant. I will use a small hose to reach the fitting since the clearance is very tight. I'll update here with my results.

[htown540i]

the suspect fitting was actually not leaking. the leaky fitting is close to the same spot, but even harder to access. looks like I'll be droping the gas tank. any tips on removing the driveline? I've never done it before.

[jase007]

looks like I'll be droping the gas tank. any tips on removing the driveline? I've never done it before.

This isn't that hard. Time consuming and some heavy [sort of] lifting involved.

If you don't have a Bentley manual and at least one [two would be better] good jacks ... go get them. Try to siphon off gas from tank before drop.

What / How to do is spelled out in bentley:

1. under body covers
2. remove exhaust
3. remove driveshaft
4. disconnect tank connections [fuel filler, electrical, vent hoses, etc...]
5. more....

Good luck.

*I've done two E30 tanks, a Suburban tank [42 gallons!!!] and other vehicles over the years.