In Reply to: Fuel smell->fuel expands when heated, pump clamps. posted by M3CSL on May 18, 2001 at 11:37:05:
Gasoline expands just like most other things when it is heated. So, if you store your car in any environment where the temperature is above the temperature of the gas (even in a garage it is warm) when it went into your tank, then the fuel in the tank will expand.
So, if you like to fill to the very top or near the top and then you drive a very short distance and leave your car in local ambient temperatures (this will be dependent on part of the country of course, but, this time of year most parts are getting warmer) it is possible that the fuel will expand. And when this happens there has to be some relief of the pressure of a liquid that will build. So, it could overflow or go through seals or something of that nature.
Then again it could also be the small POS BMW clamps on the hoses of the fuel pump or cross-over pump in your tank. You can lift up your rear bench seat and see 2 round portals to open. The hoses and clamps will be seen when you do this. Replace the POS BMW clamps with real ones and that probably would do the trick.
And, don't fill your tank to the top and then park the car in a warmer place. (people at driving schools do this all the time with the result of fuel smells and fuel spills.).