New York — The National Highway Traffic Safety Administration said Tuesday it is closing a three-year-old investigation into 281,000 Mercedes-Benz luxury cars over fuel leaks and fuel odors after the German automaker agreed to extend warranties.
The National Highway Traffic Safety Administration opened a probe in January 2012 after receiving 20 reports in 2003-2006 E55 AMG vehicles and expanded the probe last year into all 2003-2008 E-Class vehicles.
Owners said they reported a strong odor of gasoline fuel both inside and outside of their vehicle, particularly after refilling the fuel tank. Many complaints said the odor subsided after driving some distance thereby lowering the fuel level in the tank. Other owners reported they would only fill the gas tank to about three-quarters full to avoid the odor. Some owners said fuel leaked from the fuel filter/sender, located on the top of the fuel tank on the driver's side, and collected on top of the tank.
Mercedes — a unit of Daimler AG — told NHTSA on Sept. 4 it will extend the original warranty coverage to 15 years and unlimited mileage on "Covered Fuel Tank Components" in 2003-2009 E-Class vehicles in and 2006-2011 CLS-Class vehicles. Fuel tank components for the warranty extension include the fuel tank, fuel filter/sender, fuel pump, and all related gaskets/seals and retention rings. That letter was made public in recent days by NHTSA.
There were also allegations that the fuel leaks last were connected to a 2008 emissions recall campaign in 2003-2006 E-Class and CLS-Class AMG models. The issue in the emissions recall involved small cracks in the pressurized outlet fitting of the fuel filter/sender. AMG vehicles are high performance models that operate at higher fuel pressure and use a different fuel filter/sender and fuel pump than non-AMG models.
NHTSA said when the tank is full, fuel can slowly weep or seep from micro-cracks in these components and may collect in cavities on top of the filter/sender, pump, or tank. "Contrary to complainant's allegations that fuel entered the inside of their vehicle under the rear seat bench, neither (NHTSA) nor Mercedes found a plausible way for this to occur," NHTSA said. "The fuel tank is located outside of the passenger compartment, attached to the underside of the vehicle. The service access ports for the fuel filter/sender (driver's side) and fuel pump (passenger's side) are located under the rear seat bench, covered by a steel plate, sealed and bolted to the vehicle floor."
NHTSA said when technicians service the fuel filter/sender at the 60,000 mile service interval, and/or the fuel pump, "the work is performed from inside the vehicle by working through the access ports."
NHTSA said it is "closing this investigation based on the manufacturer's extend warranty of the affected fuel system components and in consideration that the nature of the leaks does not appear to present an unreasonable risk to motor vehicle safety."