Premium Unleaded Gasoline; Fuel Requirements; Gasoline Additives - Mercedes-Benz C 220 1996 Owner's Manual

Premium Unleaded Gasoline

Caution!
To maintain the engine's dura­
bility and performance, premium
unleaded gasoline must be used.
If premium unleaded is not avail­
able and low octane fuel is used,
follow these precautions:
• have the fuel tank filled only
partially with unleaded regular
and fill up with premium un­
leaded 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 operat­
ing 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, IPA,
IBA and TBA can be used provid­
ed 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 addi­
tional 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
manufacturers is carbon build up
caused by gasoline. Mercedes-
Benz recommends to use 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.
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