Mercedes-Benz Mercedes GLS 2019-present Fuel System Specifications

The 2019-Present Mercedes GLS is compatible with premium unleaded gasoline with an octane rating of 91 or higher. Using lower-octane fuel may reduce performance and fuel efficiency. Diesel variants require ultra-low sulfur diesel (ULSD). Always refer to the owner's manual for specific fuel requirements and avoid using ethanol blends above 10% to prevent engine damage.

The Mercedes GLS fuel system requires regular maintenance, including fuel filter replacement every 30,000 miles and periodic fuel injector cleaning. Use only recommended fuel additives to maintain system efficiency. Inspect the fuel tank and lines annually for leaks or damage. Adhere to the manufacturer's service schedule to ensure optimal performance and longevity of the fuel system.

To replace the fuel filter on a Mercedes GLS, first, locate the filter near the fuel tank. Disconnect the negative battery terminal for safety. Relieve fuel system pressure by removing the fuel pump fuse and running the engine until it stalls. Disconnect fuel lines and remove the old filter. Install the new filter, reconnect the lines, and secure the battery terminal. Start the engine and check for leaks.

If your Mercedes GLS has poor fuel efficiency, check for clogged fuel filters, dirty air filters, or malfunctioning oxygen sensors. Ensure tires are properly inflated and use the recommended fuel grade. Inspect the fuel injectors and consider a professional diagnostic scan to identify any engine or transmission issues affecting performance.

To optimize fuel performance, use premium fuel, maintain proper tire pressure, and avoid excessive idling. Regularly replace air and fuel filters, and ensure the engine is tuned according to the manufacturer's schedule. Drive smoothly, avoiding rapid acceleration and heavy braking. Consider using Mercedes-approved fuel additives for enhanced efficiency.