NHTSA Complaint #712110 — 1997 BMW 740

HI, I AM NOT SURE IF THIS IS A SAFETY DEFECT OR NOT. I HAD A SOUND LIKE AN EXPANDING AND CONTRACTING OF METAL IN THE BACK UNDERNEATH OF CAR. IT SOUNDED LIKE A COOKIE SHEET WHEN IT IS FIRST HEATING UP IN THE OVEN AND IT EXPANDS AND CONTRACTS. THE DEALER COULDN'T FIND ANYTHING WHEN I BROUGHT IT IN BUT SAID THAT THEY WERE GOING TO CALL BMW TECHNICAL SUPPORT BECAUSE THEY HAD A THEORY THAT A SPIDER WAS CLOGGING UP THE FUEL LINE AND THAT THIS HAD HAPPENED ONCE BEFORE TO THEIR KNOWLEDGE AND RESULTED IN THE GAS TANK COLLAPSING. I BROUGHT CAR IN AGAIN AND THEY SAID THEY REMOVED A SPIDER AND PUT IN A NEW PIPE/LINE. THE SOUND I HAD HEARD BEFORE WAS GONE. SOME PEOPLE HAVE TOLD ME, HOWEVER, THAT THE WHOLE SYSTEM IS A CLOSED SYSTEM AND THAT THIS COULDN'T HAVE HAPPENED. IS IT POSSIBLE? IS PROBLEM FIXED?