Help figure out a fuel leak (pic)

[Jean]

That's gross lol

[BigD]

So while putting on studs, i tried removing the cover off the lines to see what's going on... my car is generally rust free but all the metal in this area is rotten. All but one cover nut stud broke off. The cover itself disintegrated in my hands. I don't know if it's the fuel or what but it's freaky. It's filled with clumps of dirt too.

Anyway, the hose seems fine. But the T that connects the thick hose to the filler neck and a lead to the overflow tank is completely rotten. It fell off when I touched it, I could see some fresh fuel inside. I gotta get a better look at it but I think I need a new filler neck, cause the other end of the hose that connects the T to the filler neck is also rotten off...

It's weird too cause in the realoem diagram, there's no T. The metal line from the filler neck goes straight into the thick braided hose, and it has another nipple on it that leads to the overflow tank.



Hose that used to be on the left of that "T", more like an L now. The left side is what goes to the filler neck.



Check out the interchange around the #4 hose clamp, in my car it's a metal T, and there's a hose that connects it to the filler neck:

[Jean]

I ordered mine from BMA, i think it was 20-25 for it.

[toddz69]

I bet part 19 in this diagram.

Where can you get hose #19 at? Napa? BAP? Dealer? My car seems to be leaking there too.

Thanks,
Todd Z.

[ScottL]

Like others have suggested, there are only two places where the fuel could be exiting the tank and getting up into the wheel well during a left-hander: the top vent line or the filler neck. My money is on the vent line. (This is the hose that is wrapped in a braided sheath.)

Fuel rising up through the filler neck should spill into the overflow tank unless the cap is bad. Make sure the line coming out of the bottom of the overflow tank is OK.

I purchased a length of braided vent line from BMA - only place I could find it. They piece they sent was too short (can't specify the length when ordering) so I just spliced in part of the old one. It was a bitch to thread this hose and the two small plastic ones through the narrow tube that runs from the wheel well to the tank cavity. I did it with the tank removed - could be tough with the tank installed but if you're lucky the hose will pop out near the access panel under the rear seat.

Good luck!

[BigD]

Someone on another forum had a leak in same spot- the plastic tee a couple inches left from your circled area broke off. I dont see that part in RealOEM drawing or list. He went to a hardware store and bought a plastic tee. The clamps pictured are not reusable.
Jef Rolison

Thanks Jef! I guess the trick now is to get it to bleed with all the covers off... without driving through water this time.

[jefrolison]

Someone on another forum had a leak in same spot- the plastic tee a couple inches left from your circled area broke off. I dont see that part in RealOEM drawing or list. He went to a hardware store and bought a plastic tee. The clamps pictured are not reusable.
Jef Rolison

[BigD]

JEAN! AWESOME PICS, THANK YOU!!!

The fuel soaked spot in the pic is right here:



I'll remove the plastic cover and try to get it to leak again, that should tell the tale for sure. I have a feeling it's the braided #5 hose:



I had that accumulator thingimabob leak too, and I bypassed it with a normal fuel hose. What's the big deal about that hose, why does Real OEM show it as being 43 bucks? Do I have to get the one from the dealer or can I just get a normal fuel hose to replace it with?

Also, is this hose somewhat easy to replace? IE, can I replace it without dropping the tank, or not? If not maybe I should just cut off the leaking length for now, and add a hardpipe fitting to connect a new length of hose in its place for now...

Anyway, thanks again dude, I'll do some more investigating this week.

[Jean]

I've replaced #19 hose before and if I am looking at the picture correctly your leak is nowhere near it... here is the picture of the hose





http://www.realoem.com/bmw/showparts...07&hg=16&fg=10





Maybe pictures will help others pin point it for you

[Dave]

I can tell you this - I had a bad o-ring on the fuel pump on my 90 325i. Leaked from the same spot, and only when the tank was full. When I swapped the o-ring, there was no real accumulation of gas around the top of the tank - as it was nearing empty. When you pulled hte fuel pump cover, how much gas was in it?

For me, that fixed the problem.

[BigD]

So for clarification, the pic is of the right rear wheel well, with the wheel well cover removed?

Yup, the overflow/expansion tank is in the upper left corner in the shadow in the pic.

[Mike325]

So for clarification, the pic is of the right rear wheel well, with the wheel well cover removed?

[BigD]

That hose is right infront of the rear subframe. It goes over the TA.

Yeah but it goes in closer to the center of the chassis. Unless I'm wrong, my leak is right inside the wheel well somewhere. Like I said the darkness around that nut in the pic is gasoline. I gotta try to reproduce the leak strongly so there is no doubt where it's leaking. So far I'm still not 100% - but that dark spot around that nut is gas and that's around where I remember the leak coming from.

[Mike325]

That hose is right infront of the rear subframe. It goes over the TA.

[BigD]

Doesn't that hose end around the axle, or even infront of it? Or is it behind that cover that is soaked in gas (the pic is from behind the wheel).

No, the tank itself is dry, the leak is behind the wheel, not infront of it.

Thanks guys!