291 Operation
At the gas station
At the gas station
Refueling
The fuel filler flap is located on the 
right-hand side of the vehicle towards the 
rear.
Locking and unlocking the vehicle with the 
SmartKey automatically locks and unlocks 
the fuel filler flap.1To open fuel filler flap
2To insert fuel filler cap
Remove the SmartKey from the starter 
switch.
Open fuel filler flap by pushing at point 
indicated by arrow1.
The fuel filler flap springs open.
Turn fuel filler cap counterclockwise 
and hold on to it until possible pressure 
is released.
Take off fuel filler cap and set it in 
direction of arrow2 in the recess on 
the inside of fuel filler flap.
To prevent fuel vapors from escaping 
into open air, fully insert filler nozzle 
unit.
Only fill your tank until the filler nozzle 
unit cuts out – do not top off or 
overfill. 
Replace the fuel filler cap by turning it 
clockwise until it audibly engages.
Warning!G
Gasoline is highly flammable and poisonous. 
It burns violently and can cause serious 
personal injury.
Never allow sparks, flame or smoking mate-
rials near gasoline!
Turn off the engine before refueling.
Whenever you are around gasoline, avoid 
inhaling fumes and skin contact, extinguish 
all smoking materials.
Direct skin contact with fuels and the 
inhalation of fuel vapors are damaging to 
your health.
iIn case that the central locking system does 
not release the fuel filler flap, or the opening 
mechanism is clamping, contact Roadside 
Assistance or an authorized Mercedes-Benz 
Center.
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.
 
292 Operation
At the gas station
Close the fuel filler flap.
Check regularly and before a long trip
Engine compartment 
(example illustration, SLK 350)
1Windshield washer system and head-
lamp cleaning system* reservoir
2Brake fluid reservoir
3Coolant expansion tankWindshield washer system and head-
lamp cleaning system*
For information on refilling the reservoir, 
see “Windshield washer system and 
headlamp cleaning system*” 
(
page 301).
Brake fluid
For information on brake fluid, see “Fuels, 
coolants, lubricants, etc.” (
page 451).
iMake sure to close the fuel filler flap before 
locking your vehicle as the flap locking pin 
prevents closing after you have locked the 
vehicle.
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. Please contact gas 
station personnel in case labels on the pump 
cannot be found.
For more information on gasoline, see “Premium 
unleaded gasoline” (
page 454), refer to the 
Factory Approved Service Products pamphlet 
(USA only), or contact an authorized 
Mercedes-Benz-Center.
iLeaving the engine running and the fuel cap 
open can cause the yellow fuel tank reserve 
warning lamp to flash and the?malfunction 
indicator lamp (USA only) or the 
±malfunction indicator lamp (Canada only) 
to illuminate.
For more information, see “Practical hints” 
(
page 351).
iFor opening the hood, see “Hood” 
(
page 294).
!If you find that the brake fluid in the brake 
fluid reservoir has fallen to the minimum mark or 
below, have the brake system checked for brake 
pad thickness and leaks immediately. Notify an 
authorized Mercedes-Benz Center immediately. 
Do not add brake fluid as this will not solve the 
problem.
For more information, see “Practical hints” 
(
page 350).