02 4.6is - Gas Overflow
 

Before turkey day, I was filling up my X5 at Shell on the slowest setting, which I always do. The tank became full to the point that it blew the fuel pump under the rear seat out of its "seat" and gas went everywhere / on the ground.

I had it towed to a shop and they found the issue, resealed it and away I went. Well, tonight I went back to the same gas station and used the same pump and it happened again. I went home and took the rear bench out, removed the lid and tried to get it to re-seat but had no luck. I watched a couple videos explaing it to be sure i wasn't missing anything as well. Not sure if the pump kick-off is failing or this near 20 year old marvel of german engineering.

Is there a wear item i need to replace? It makes me a bit mad that something as simple as this is not made to last.

Thanks for the help & advice. Im heading over to realoem to see if there's anything I can replace on that stupid collar.

BMW official stance is to replace the seal if you enter the tank, but I’ve always reused the seal they never showed any sign of wear.

I made a special wrench to properly remove and more importantly tighten the collar so it’s even.

The trick to installing the seal is it must go into the tank and then the pump unit gets reinstalled.

Was the gas leaking around the main seal or somewhere else?

I sense you have a defective seal that this would happen. Did the shop replace the seal or just re place the seal?

They just put it back together. Ill head over to FCP and order a new seal and the metal lock collar for good measure. $15 for both parts new. I may have to pump some fuel out. I might order 2, so both sides get done. This is some horse shit.

Its very full. :(

You may have a blocked vent that causes the tank to pressurise when filling... or the pump at that station is VERY fast...:dunno:

curious about the slow fill procedure. There is no reason to suffer though the whole fill at slow speed.

If you want a complete fill, start at high speed then when it clicks off then do the slow speed fill.

It’s not uncommon for cars to bleed into the ground when filled too slowly, are you sure the leak was around the main seal and not though the overflow?

Yeah, once you remove the access panel under the bench, the pump/sending unit was literally just laying the the tank.

The old o-ring would not seat properly, but the new metal collar and o-ring arrived yesterday and fit perfectly. Ill have to see what happens after this tank of fuel on the next refill.

I don't understand how your fuel pump got blown out of the rubber seat.
With the locking collar in place, it is impossible for the fuel pump to come out.

I can only posit that due to the cell being plastic that, like a milk carton, when pushed to the limit it deforms allowing it to blow off. It's happened twice, this last time I reassembled with new seal/collar and tightened it myself. I thought it odd too, but this is a thing that happens according to friends that run shops. :dunno:

Feels like a CV Mfg Defect to me. Hope it was the seal or collar not the tank. The gas filler neck should not be a tight enough seal to pressurize from the pump so it’s quite surprising.

Thinking that though i think it’s more likely you have a problem on the atmospheric vent and the damage occurred not when you pumped but before so I would get that looked into.


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