740i Fuel tank imploded.

The fuel tank on my 1997 740i has been building up great amounts of pressure. It is almost impossible to get the gas cap off and then when it does come off there is a huge "whoosh" sound from pressure release. My mechanic said to get a new ventilated fuel cap but problem remained. My fuel tank on the drivers side has actually imploded and is sitting in my garage leaking gas. This problem is also causing the fuel to stop flowing when I get down to 1/4 tank. BMW says there is no recall on this issue. Seems like a dangerous situation to me.

Yeah pretty common thing it seems. It's generally related to the charcoal canister, which was actually redesigned on 3/97 and later models to try and avoid this particular issue. What specific month model is your car? It's possible yours was built just prior to this change coming into effect (remember there's a difference between the PRODUCTION date and build date - my car is a 1996 build but production was in 95 for my motor, if I've got that right).

Have a read here, it's a well known issue;

http://www.e38.org/SI.New.Evaporativ...Purge.Line.pdf

No recalls issued by BMW that I'm aware of!

Mine is going the same way - stealer quoted $300 for change over. BTW the cap is not vented - unless you drill it.

'97 - can't drill since OBDII if I'm not mistaken-- the goods have already been posted. Good luck.

Our Ausi spec cars wouldn't know or be able to tell if a cap was drilled - sorry about the mis-info.

Yep we drill the cap in the UK too as no one has found the solution to this. Some have changed the charcoal cannister with no effect..