Two problems related to other fuel system tank assembly have been reported for the 1997 BMW 740. The most recently reported issues are listed below.
My wife and I purchased this vehicle at a certified used dealership. We fueled it up and drove it around that night and parked it at our home. The next morning it smelled terribly of gasoline so I looked under the car. The driver's side of the fuel tank was crushed in and it was pouring gasoline all over the driveway. Their was a puddle approximately 3 feet wide under the car. I had it towed to the dealer and they were shocked. We both assumed that they never filled the talk so the problem wasn't known. They replaced the tank free of charge and once again I filled the tank and drove it around for the weekend. I noticed the gasoline smell again and looked under the car and was shocked to see the tank crushed in again and the fuel leaking out. I ran a google search on this and found out that I was not alone. There is a known problem with a purge line that causes the talk to implode on itself. I am very surprised to not find a recall on this. I would think that avoiding a car fire would be a concern for the nhsta. I hope with enough complaints they force a recall.
Purchased a "certified" BMW 1997 740il in 11/02 with 69,000 miles. In January I noticed a "tin can" popping sound from the rear of the vehicle and a vacuum like sound when opening the gas cap to fuel. I noticed that the driver side gas tank had a dent in it although I had not hit anything. I took the vehicle to john roberts BMW in dallas. The service advisor told me that they had never had any complaints resembling mine and that I must have struck something to damage the tank. About one month later the tank began to leak and basically imploded from vacuum pressure. I posted my experience on several web sites and received over 20 responses from owners who had the same problem. One of these people sent me a technical bulletin from BMW to its dealers describing the problem as a fuel tank vent which would become stopped up and cause the fuel tank to implode. I went back to the dealer but by this time my vehicle was one month out of warranty. I believe this defect is a potentially deadly hazard and could have easily resulted in an explosion or fire.