Fuel filler neck

[73tiiPolaris]

This is my first post on this forum, which has been hugely helpful to me on several occasions already as a recent purchaser of a 1973 2002tii. I'm reaching out to see if folks can confirm that I have the right components on the fuel supply system, and especially the filler neck. I've been trying to fix a gas smell in the trunk, and would like to make sure I don't have mismatched parts given that the style of the filler neck and flange changed over time. I'm including a picture of the current filler neck with its retaining ring secured, and another showing that ring unbolted and the neck pulled back to reveal the flange underneath.

 

I've read the many posts on this forum about the "gas smell" topic, and have considered the many potential causes identified in those posts. E.g., cracks in the filler neck or fuel lines, or a faulty or missing gasket or o-ring. I've discovered that I do indeed have a missing gasket on the fuel filler neck, as you can see in the second picture. I'm guessing that the white residue is the remnants of what was once a gasket. When I install a new gasket it will hopefully fix the problem, but for good measure I've also ordered a new gasket for the fuel pick-up in case that's another contributor. The o-ring on the fuel level sender has already been replaced and the fuel lines look new and sound. The breather line runs into the plastic canister and then on to the engine bay, rather than out the trunk the European way.

 

I have inspected the filler neck and cannot find any cracks in the rubber. I'd order a new one anyway just in case, but they're not cheap (about $100). However, I will definitely order a new one if anyone thinks the one on there now looks problematic. Any input would be appreciated. Thanks.

 

 

 

 

 

[Mikesmalaga72]

Looks like you are missing the red paper gasket number 11 that goes between neck and body flange.

It can be a bear unless you use picks to keep the sandwich lined up also the mounting screws look different from original so open the holes on gasket accordingly. Make sure you can torque / snug down the bolts. lack of snugging screws down can cause fluid leaks/odors. 

 

https://www.realoem.com/bmw/enUS/showparts?id=2215-USA-12-1975-114-BMW-2002&diagId=16_0384

 

Edited June 21 by Mikesmalaga72
add

[73tiiPolaris]

@Mikesmalaga72, those are great tips -- thank you. I have that gasket on order and will definitely use picks or awls to hold it in place while the other screws go in. I'm assuming that some Hylomar blue on both sides of the gasket might help promote a good seal, but please let me know if anyone thinks that's incompatible with a paper gasket.

 

I'm wondering now if I should get different bolts to try to match the originals. If anyone has a suggestion about what size or type the bolts should be, please let me know. Thanks.

[Mikesmalaga72]

Metal flange side Hylomar rubber flange side dry for servicing neck. If neck snugs down sufficiently use the ones you already have. The original screws have been NLA for years. 

Edited June 21 by Mikesmalaga72

[Mark92131]

I would be a little concerned that any gas leaking past the gaskets would soak in that grey carpet material and perpetuate the gas smell.  RealOEM says 4 sheet metal screws, not bolts, part # 16111111170.

 

Mark92131

[Mikesmalaga72]

1 minute ago, Mark92131 said:

I would be a little concerned that any gas leaking past the gaskets would soak in that grey carpet material and perpetuate the gas smell.  RealOEM says 4 sheet metal screws, not bolts, part # 16111111170.

 

Mark92131

It does look pretty close there!

[Mikesmalaga72]

I would make a larger radius in that carpet hole to clearance away from that flange as well as Mark said.

[73tiiPolaris]

I'm so glad I made this post. Such helpful input! I'll put the hylomar on the metal side only. The carpet piece is quite small and looks easy to remove so when I have the filler neck off I will address it as necessary. If it has a fuel smell I will try to clean it and I will definitely enlarge the hole.

 

Regarding the sheet metal screws, part number 16111111170 doesn't seem to be available anymore but I'm hoping I can find a substitute. Does anyone know the size and length of the correct screws? The bolts on there now are 7 mm.

[Mikesmalaga72]

Are those screws not snugging up with your current setup? measure the shank of the screw. 

[73tiiPolaris]

The bolts seem to go in and come out fine, and from what I can tell they snug up properly. So maybe they're fine as is?

 

I'm attaching another picture -- this time showing a better view of the flange behind the carpet -- in the hope of confirming that the flange is correct. I note that my flange is a silver color, whereas others that I've seen for sale or in photos on this site are brass-colored.

 

There seem to be any number of places from fuel spout to tank where an imperfect fit could allow fumes to escape ...

[Mikesmalaga72]

If the screws hold well then you should be okay. You may want to inspect the fuel hoses at their connections near fuel tank the cloth covered ones can weep, also at the fuel outlet plastic sleeve on the sending unit outlet connection can crack and seep. I have the vent hose from the neck running to the outside under the trunk floor Euro style.

Edited June 21 by Mikesmalaga72

[Son of Marty]

How is your tank vent routed?

[Preyupy]

Also the seals around the fuel level sender and the plate with the fuel lines. They are both below the fuel level when you fill the tank and have fuel to the top of the filler neck.  Also have a good look around the flange that runs around the tank, if there is any rust you might have a pinhole around there.  

[TobyB]

...and this might be just the picture, but your boot looks like it's oddly stretched-

is that an earlier, longer- necked tank?

 

If so, as above, a fuel- resistant sealant really helps, as there's no sealing lip to aid with

the rubber- to- metal interface.

 

Or, alternately, make sure nothing's bent- if it all doesn't align well, it'll be hell to get it to seal.

 

fwiw,

t

 

[73tiiPolaris]

Thanks for all of these comments. I'm posting another picture that shows how everything fits together. I'm not sure what version of tank or filler neck I have, but perhaps others will be able to tell from the photo.

 

To answer @Son of Marty's question, there is a breather line that runs from the filler neck to a plastic canister and another from there on to the engine bay. Those are the only vent lines I'm aware of.