Hey guys, I have a strange issue which I think I've narrowed down to me repeatedly overfilling my E92 335i fuel tank incorrectly at United, but I'd rather be safe and gather some thoughts.
Issue came up immediately a couple of weeks ago after doing an LPFP upgrade and mixing some E85 at United. I definitely overfilled the car a little (made the pump trigger click 2 or 3 times all up) on the first occasion and the car dumped a litre or two of fuel. Didn't think much of it as I figured it was slightly overfilled.
Filled up the next week (upto around 90-95%) at a different servo. No issues or leaks.
Following week I filled up to 100% again at United (filled up to the first click and then stopped). Fuel leaked again, in the same manner.
The fuel leaks don't appear major (as they seem to stop completely after the car gets down to about ~90% fuel level), but they are a hazard, and I'm not sure whether I had inadvertently broken something with the initial overfill.
The fuel leak itself originates from around the rear end of the driver's side rear wheel well - there is a tube in that area that appears to run from the centre (or passenger's side) of the fuel tank to there. Anyone know if that tube is made to dump excess fuel and where it runs to? Is it a breather for the fuel filter?
Here's a pic of the rough area where it was leaking (I'll grab better photos of my car and with the guard liner removed if needed):
I've confirmed the fuel leak is indeed coming from the aforementioned tube situated in that area, and
not the fuel filler neck/breather pipes that are more to the right and known to sometimes leak. No signs of any leaks whatsoever underneath the driver's side rear seat (LPFP location) or anywhere else.
Funnily enough, I added about 10L of fuel with a jerry can last night (to bring it up to about 95% and see if it would leak), but the car didn't leak at all even after a short drive.
Is there anything else I can check, or do I just need to be more careful when filling up? Haha
Any help would be appreciated!