Mercedes-Benz Cls 500, Operator'S Manual

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434
Technical data
Fuels, coolants, lubricants etc.
Fuel requirements
Only use premium unleaded gasoline
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 Mo-
tor (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.
Coolants
The engine coolant is a mixture of water
and anticorrosion/antifreeze, which pro-
vides:
앫
Corrosion protection
앫
Freeze protection
앫
Boiling protection (by increasing the
boiling point)
The cooling system was filled at the factory
with a coolant providing freeze protection
to approximately -22°F (-30°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).
The coolant solution must be used
year-round to provide the necessary corro-
sion protection and increase boil-over pro-
tection. Refer to Maintenance Booklet for
replacement interval.
Coolant system design and coolant used
determine the replacement interval. The
replacement interval published in the
Maintenance Booklet is only applicable if
MB 325.0 anticorrosion/antifreeze solu-
tion or other Mercedes-Benz approved
products of equal specification (see
Factory Approved Service Products pam-
phlet) are used to renew the coolant con-
centration or bring it back up to the proper
level.