Mercedes-Benz S-Class Automobile User Manual


 
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Technical data
Fuels, coolants, lubricants, etc.
Premium unleaded gasoline Fuel requirements
Use only premium unleaded fuel:
ț The octane number (posted at the
pump) must be 91 min. It is an average
of both the Research (R) octane num-
ber and the Motor (M) octane number:
(R+M)/2). This is also known as the
ANTI-KNOCK INDEX.
Unleaded gasoline containing oxygenates
such as Ethanol, IPA, IBA and TBA can be
used provided the ratio of any one of these
oxygenates to gasoline does not exceed
10%; MTBE must not exceed 15%.
The ratio of Methanol to gasoline must not
exceed 3% plus additional co-solvents.
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 manufac-
turers is carbon build-up caused by gaso-
line. Mercedes-Benz recommends only the
use of quality gasoline containing additives
that prevent the build-up of carbon depos-
its.
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 en-
gine performance problems such as:
ț Warm-up hesitation
ț Unstable idle
ț Knocking/pinging
ț Misfire
ț Power loss
!
To maintain the engine’s durability and
performance, premium unleaded gaso-
line must be used. If premium unleaded
gasoline is not available and low octane
fuel is used, follow these precautions:
ț Have the fuel tank only partially
filled with unleaded regular and fill
up with premium unleaded as soon
as possible.
ț Avoid full throttle driving and abrupt
acceleration.
ț 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.
ț Do not exceed 2/3 of maximum
accelerator pedal position if the ve-
hicle is fully loaded or operating in
mountainous terrain.