There are 12 owner-reported fuel system complaints for the 2004 Mercedes-Benz SL-Classin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
On many 2003 and 2004 models. Broken fuel tank baffle inside fuel tank. This is well documented and could possibly cause explosion.
ON JULY 22, 2020 THE VEHICLE (2004 MERCEDES-BENZ SL500 (R230)BEGAN MAKING A LOUD BANGING NOISE IN THE REAR WHEN STOPPING AND TURNING. I DELIVERED THE VEHICLE TO A LOCAL SHOP WHERE THE VEHICLE WAS DIAGNOSED AS HAVING A BROKEN BAFFLE IN THE FUEL TANK. THE ONLY SOLUTION IS TO REPLACE THE ENTIRE FUEL TANK. MANY OTHER OWNERS OF THIS MODEL HAVE EXPERIENCED THE SAME ISSUE AND IS CLEARLY A MANUFACTURER DEFECT; THIS CANNOT BE CAUSED BY EXCESS WEAR ON THE VEHICLE. BECAUSE THERE IS NOW A LARGE SECTION OF THE FUEL TANK FREELY SWINGING INSIDE, THERE IS A CHANCE THAT THIS COULD CAUSE A SPARK AND SUBSEQUENT EXPLOSION. I CANNOT SAFELY DRIVE THIS VEHICLE UNTIL THE FUEL TANK IS REPLACED AT A VERY LARGE COST. THIS MODEL SHOULD HAVE BEEN RECALLED WHEN THIS ISSUE WAS FIRST COMING TO LIGHT OVER 15 YEARS AGO.
I EXPERIENCE A STRONG ODOR OF FUEL WHEN ENTERING MY VEHICLE AND WHEN DRIVING THE VEHICLE, ALSO WHEN DRIVING THE VEHICLE I HEART A LOUD THUMPING SOUND COMING FROM THE TRUNK AREA. SOUNDS TO ME AS THOUGH SOMETHING IS FLOATING INSIDE GAS TANK. THIS ODOR HAS SICKENED ME AND HAS SEVERELY UPSET MY STOMACH TO THE POINT THAT I'M UNABLE TO DRIVE MY VEHICLE EXCEPT FOR A SHORT DISTANCE. THE THUMPING SOUND IS CREATED WHEN VEHICLE IS MOVING OR COMING TO A STOP BUT HAPPENS CONTINUOUSLY WHILE DRIVING. *TR
TL* THE CONTACT OWNS A 2004 MERCEDES-BENZ SL500. WHEN THE VEHICLE WAS STARTED, THE CONTACT HEARD AN ABNORMAL KNOCKING SOUND UNDERNEATH THE VEHICLE NEAR THE FUEL TANK. ADDITIONALLY, THERE WAS A CONSTANT FUEL ODOR INSIDE THE VEHICLE. THE VEHICLE WAS TAKEN TO MERCEDES-BENZ OF VIRGINIA BEACH (LOCATED AT 4949 VIRGINIA BEACH BLVD, VIRGINIA BEACH, VA 23462, (757) 499-3771) WHERE IT WAS DIAGNOSED THAT ONE OF THE BAFFLES IN THE FUEL TANK FRACTURED, SEPARATED, AND NEEDED TO BE REPLACED. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS NOT NOTIFIED. THE APPROXIMATE FAILURE MILEAGE WAS 144,000. THE VIN WAS NOT AVAILABLE.
TL* THE CONTACT OWNS A 2004 MERCEDES BENZ SL500. THE CONTACT STATED THAT WHILE DRIVING AT VARIOUS SPEEDS, A KNOCKING NOISE EMITTED FROM THE REAR DRIVER'S SIDE. THE DEALER DIAGNOSED THAT FUEL TANK NEEDED TO BE REPLACED. THE VEHICLE HAD NOT BEEN REPAIRED. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE. THE VIN WAS UNAVAILABLE. THE APPROXIMATE FAILURE MILEAGE WAS 78,000.
THE GAS TANK BAFFLE HAD BROKEN AND IT IS KNOCKING INSIDE THE TANK. I AM CONCERNED THAT IT WILL BREAK AND CAUSE A FIRE. *TR
TL* THE CONTACT OWNS A 2004 MERCEDES BENZ SL600. THE CONTACT STATED THAT WHILE DRIVING 50 MPH, THE VEHICLE STALLED. THE VEHICLE WAS TAKEN TO A DEALER WHERE THE TECHNICIAN DIAGNOSED THAT THE FUEL TANK NEEDED TO BE REPLACED. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS MADE AWARE OF THE FAILURE. THE FAILURE MILEAGE WAS 40,000 AND THE CURRENT MILEAGE WAS 40,100.
A POUNDING NOISE (LIKE A HAMMER HITTING A 2X4) OCCURRED REPEATEDLY WHENEVER I STARTED OR STOPPED. IT TURNED OUT TO BE A FAILURE OF THE BAFFLES INSIDE THE GAS TANK AND REQUIRED A REPLACEMENT OF THE GAS TANK AT A COST OF OVER $2000. THIS IS CLEARLY A DEFECT IN MATERIALS OR WORKMANSHIP AND SHOULD BE THE SUBJECT OF A RECALL. THE BAFFLES SLIDING AROUND THE TANK WOULD ULTIMATELY CAUSE IT TO LEAK IF THE TANK WERE NOT REPLACED. THE DEALER WOULD NOT PAY FOR THE REPLACEMENT. IT HAS APPARENTLY OCCURRED ON MANY MERCEDES CARS ACCORDING TO THE INTERNET REPORTS. *JS
2004 MERCEDES-BENZ SL500, LOUD KNOCKING NOISE FROM THE REAR.FUEL TANK MIGHT NEED TO BE REPLACED... SEEMS TO BE A COMMON PROBLEM WITH THESE CARS. *TR
BAFFLE IN MY FUEL TANK ON MY 2004 MERCEDES SL 500 HAS BROKEN. CAUSES A LOUD KNOCKING SOUND. ENTIRE FUEL TANK HAS TO BE REPLACED. RESEARCHING MANY BLOGS AND FORUMS FOUND MANY OF SL OWNERS HAS SAME EXPERIENCED. I BELIEVE THIS SHOULD BE HANDLED UNDER A RECALL FROM THE MANUFACTURER. *TR
BAFFLE IN MY FUEL TANK ON MY 2004 MERCEDES SL 500 HAS BROKEN. CAUSES A LOUD KNOCKING SOUND AND THE ONLY REMEDY IS TO SPEND $3000 TO HAVE THE ENTIRE FUEL TANK REPLACED. THIS IS HAPPENING TO HUNDREDS OF MERCEDES BENZ SL OWNERS. I BELIEVE THIS SHOULD BE HANDLED UNDER A RECALL FROM THE MANUFACTURER. *TR
KNOCKING NOISE BEGIN TO APPEAR BEHIND THE DRIVER'S SEAT. AT FIRST, BELIEVED TO BE LOOSE ITEM IN THE TRUNK BUT CHECK AND CAN'T FIND. LOOKED AT FORUM AND FOUND THAT MANY 2003/2004 MERCEDES BENZ SL CLASS HAS THE SAME PROBLEM WITH DEFECTIVE GAS TANK BAFFLE. WHENEVER I BRAKE OR ACCELERATE, I HEAR THE KNOCKING NOISE, WHICH ALSO KNOCKS TWO OR THREE TIMES EVERYTIME I BRAKE OR ACCELERATE. IT SOUNDS LIKE SOMETHING IS HANGING FROM A STRING OR FLOATING AND THEN BECAUSE OF INERTIA IT KNOCKS AGAINST THE SIDE OF A CONTAINER. THE HAZARD THAT I FEAR IS THAT THE FLOATING MATERIAL IN THE GAS TANK KNOCKS AGAINST THE TANK AND CREATE A SPARK THAT CAN IGNITE THE TANK CAUSING A FIRE. THE KNOCKING NOISE HAPPENS EVERYTIME THE CAR JERKS FROM BRAKING OR ACCELERATING. *TR
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 25, 2026