Mercedes-Benz 2004 G 500 Automobile User Manual


 
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Technical data
Fuels, coolants, lubricants, etc.
Fuel requirements
Use only premium unleaded meeting
ASTM standard D 439:
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 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
Do not blend other specific fuel additives
with fuel. This only results in unnecessary
cost and may be harmful to the engine op-
eration.
Damage or malfunctions resulting from
poor fuel quality or from blending specific
fuel additives are not covered by the
Mercedes-Benz Limited Warranty.
Coolants
The engine coolant is a mixture of water
and anticorrosion/antifreeze, which pro-
vides:
ț Corrosion protection
ț Freeze protection
ț Boiling protection (by increasing the
boiling point)
The cooling system was filled at the factory
with a coolant providing freeze protection
to approximately -35°F (-37°C) and corro-
sion protection.
If the antifreeze mixture is effective to
-22°F (-30°C), the boiling point of the cool-
ant in the pressurized cooling system is
reached at approximately 266°F (130°C).