Mercedes-Benz G-Class 2006 Owners Manual - Manual (Page 380)

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Technical data
Fuels, coolants, lubricants, etc.
Fuel requirements
Only use 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 cosolvents.
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
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:
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
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 per-
sons and no luggage.
ț Do not exceed
2
/
3
of maximum ac-
celerator pedal position if the vehi-
cle is fully loaded or operating in
mountainous terrain.