270 OperationAt the gas station
Replace the fuel cap by turning it to the
right.
You will hear when the fuel cap is tight-
ened.
Close the fuel filler flap.
Check regularly and before a long trip
1Windshield washer and headlamp
cleaning system*
2Coolant level
3Brake fluid
Warning!
G
Overfilling of the fuel tank may create pres-
sure in the system which could cause a gas
discharge. This could cause the gas to spray
back out when removing the fuel pump noz-
zle, which could cause personal injury.
iOnly use premium unleaded gasoline
with a minimum Posted Octane Rating
of 91 (average of 96 RON / 86 MON).
Information on gasoline quality can
normally be found on the fuel pump.
More information on gasoline can be
found in the Factory Approved Service
Products pamphlet.iLeaving the engine running and the fuel
cap open can cause the ? malfunc-
tion indicator lamp to illuminate.
For more information, see the “Practi-
cal hints” section (
page 306).
iOpening the hood, see (
page 272).
394 Technical dataFuels, coolants, lubricants, etc.Brake fluid
During vehicle operation, the boiling point
of the brake fluid is continuously reduced
through the absorption of moisture from
the atmosphere. Under extremely strenu-
ous operating conditions, this moisture
content can lead to the formation of bub-
bles in the system, thus reducing the sys-
tem’s efficiency.
Therefore, the brake fluid must be re-
placed every two years, preferably in the
spring.
Only brake fluid approved by
Mercedes-Benz is recommended. Your au-
thorized Mercedes-Benz Center will pro-
vide you with additional information.
Premium unleaded gasoline
Fuel requirements
Use only premium unleaded fuel:
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 co-solvents.
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.
!To maintain the engine’s durability and
performance, premium unleaded gaso-
line must be used. If premium unleaded
gasoline is not available and low octane
fuel is used, follow these precautions:
Have the fuel tank only partially
filled with unleaded regular and fill
up with premium unleaded 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 ve-
hicle is fully loaded or operating in
mountainous terrain.
