Mercedes Benz 2007 sl 550 User Manual

Only use premium unleaded fuel:

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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.

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 engine performance problems such as:

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Warm-up hesitation

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Unstable idle

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Knocking/pinging

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Misfire

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Power loss