Premium-grade unleaded gasoline

performance of the engine, only premiumgrade To ensure the longevity and full performance of the engine, only premiumgrade unleaded gasoline may be used.
If there is no premium-grade unleaded gasoline available and regular-grade unleaded gasoline may be used; please observe the following precautions:
• only fill the fuel tank to half full with regular-grade unleaded gasoline and fill the rest with premium-grade unleaded gasoline as soon as possible.
• do not drive at the maximum speed.
• avoid sudden acceleration.
• if the vehicle is carrying a light load, e.g. two passengers without luggage, do not allow the engine to rev above 3,000 rpm.
• if the vehicle is fully loaded or is being operated in mountainous terrain, do not depress the accelerator pedal further than 2/3 of the pedal travel.

    See also:

    Seating & Cargo
    The GL550's front seats have a litany of power adjustments, including adjustable stiffness for the side bolsters. Even with the bolsters and lumbar support dialed all the way back, the seats are t ...

    Safety
    Antilock brakes have Brake Assist for automatic full-power braking in panic stops. Electronic brake-force distribution enhances stability when braking in curves. ...

    Restoring the factory settings
    Press the and buttons simultaneously for approximately six seconds until the battery check lamp flashes twice. ...