Premium Unleaded Gasoline
Caution !
To maintain the engine's durability and performance, premium unleaded gasoline must be used. If
premium unleaded is not available and low octane fuel is used, follow these precautions:
• have the fuel tank filled only partially with unleaded regular and fill up with premium unleaded
as soon as possible,
• avoid full throttle driving and abrupt acceleration,
• do not exceed an engine speed of 3000 rpm, if the vehicle is loaded with a light load such as two
persons and no luggage,
• do not exceed 2/3 of maximum accelerator pedal position, if the vehicle is fully loaded or operating
in mountainous terrain.
Fuel Requirements
Use only Premium unleaded meeting ASTM standard D 439: The octane number (posted at the
pump) must be 91 min. It is an average of both the Research (R) octane number and the Motor (M)
octane number: [(R+M)/2]. This is also known as ANTI-KNOCK INDEX. Unleaded gasoline
containing oxygenates such as Ethanol, I PA, IBA and TBA can be used provided the ratio of any
one of these oxygenates to gasoline does not exceed 10%, MTBE not to exceed 15%. The ratio of
Methanol to gasoline must not exceed 3% plus additional components. Using mixtures of Ethanol
and Methanol is not allowed. Gasohol, which contains 10% Ethanol and 90% unleaded gasoline, can
be used. These blends must also meet all other fuel requirements such as resistance to spark
knock, boiling range, vapor pressure etc..
Gasoline Additives
A major concern among engine manufacturers is carbon build up caused by gasoline. Mercedes-
Benz recommends the use of only quality gasoline containing additives that prevent the build up of
carbon deposits. After an extended period of using fuels without such additives, carbon deposits can
build up especially on the intake valves and in the combustion area, leading to engine performance
problems such as:
• warm-up hesitation,
• unstable idle,
• knocking/pinging,
• misfire,
• power loss.
Do not blend other specific fuel additives with fuel. They only result in unnecessary cost, and may be
harmful to the engine operation. Damage or malfunctions resulting from poor fuel quality or from
blending specific fuel additives are not covered by the Mercedes-Benz Limited Warranty.
