Fuel Requirements - Mercedes-Benz 300 SL Operator's Manual

Fuel Requirements

Use only Premium unleaded meeting
ASTM standard D 439:
The octane number (posted at the
pump) must be 91min. 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 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
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.
Damages or malfunctions resulting
from poor fuel quality are not covered
by the Mercedes-Benz Limited
Warranty.
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