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Fuel Leak when filling full tank - Petrol cars

zippy_20052010-08-17 20:34:06 +0000 #1

I have read quite a bit over the internet about many E9x users reporting their diesel cars leaking fuel when filling a full tank/to the brim and it starts to drip in front of the OSR wheel.

Turns out that the breather hose gets chafed against a sharp edge of the bodywork the hose passes against.

A few weeks ago, I had the same problem - but mine is a petrol E90, which uses the same breather pipe hose as on the diesel cars, however I am yet to find a petrol owner who has had this issue, anywhere on forums or the internet.

My car is 4 1/2 years old has been fixed now after getting BMW UK involved with my local dealer. Both my dealer and BMW UK contibuted to the cost of the repair even though I believe I should not have to pay anything for this as it is a fundamental design error on BMW's part. As the part is not exposed to the customer and cannot be damaged by any external influnences i.e. road debris as the pipe is fitted behind the wheel arch liner - no customer should be liable to pay for this.

My car is out of warranty but a fuel leak without warning to the driver is a serious issue for any car manufacturer.

I have since filed a vehicle defect report to VOSA who are leading this with BMW and I guess I will find out in due course the outcome and if they will force BMW to carry out a recall.

People who have diesel cars that have leaked due to the pipe being chafed is more noticeable than petrol cars as diesel will drip and leave a residue on the road/driveway, so you know there is a problem. As for petrol, because it evaporates quickly, you may miss the leak.

My concern is that there may be petrol cars out there which drivers fill up and are unware of such a leak when filling a full tank.

I mentioned to VOSA this risk and I witness a prime sceanrio on the road the other day - a car next to me decided to throw their live cigarette stub out of the window next to my car. Now had I just filled up a full tank of petrol and it was leaking - boom!

All petrol E9x users, please check your vehicles by filling a full tank of petrol and note if it leaks in front of the OSR wheel.

BMW need to react to this in a more urgent matter and get this fixed for other drivers. They know it is an issue as they have since modified the breather pipe hose by adding a tougher corregutated sleeve over the exsisting pipe to further protect it from being chafed.

Some photos added to aid this thread... one of the photos shows the breather hose next to a sharpe edge of metal - which has chafed the pipe. There are two photos showing the modification to the pipe, the extra tubing over the breather hose as it enters the wheel arch cavity.







Any questions, please ask and I will help answer any concerns.

VTECaddict2010-08-17 20:39:57 +0000 #2
Are you OVERfilling your tank? You keep saying filling a full tank...are you trying to fill it even more after the pump auto stops? Or does it leak even if you just stop pumping when the pump stops?
zippy_20052010-08-17 20:57:27 +0000 #3
Even when the pumps cuts out, this is when the tank is virtually full, petrol will start to drip.

It definitely was not overfill petrol that leaking from the filler neck and the filler neck itself in the wheel arch is completely dry.

I have kept the actual part removed from my car and you can see where the pipe has been cut over time, so it's definitely the breather pipe.

Something to remember is when a tank of petrol is fully filled, the volume of petrol will equalise in the tank and its associated hoses, so once level, there will be some fuel in the breather pipe and this is where it leaks from until the level of petrol drops below the cut and then the leak will stop.


Originally Posted by VTECaddict

Are you OVERfilling your tank? You keep saying filling a full tank...are you trying to fill it even more after the pump auto stops? Or does it leak even if you just stop pumping when the pump stops?



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