Page 172 of 314

172 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.
You should hear the latch close shut.
Check regularly and before a long trip
1Windshield washer and headlamp
cleaning system*
More information on filling up the res-
ervoir can be found in the “Operation”
section (
page 184).
2Brake fluid3Coolant level
More information on coolant can be
found in the “Operation” section
(
page 180).
4Engine oil level
More information on engine oil can be
found in the “Operation” section
(page 175).
Opening hood (
page 174).
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.iLeaving the engine running and the fuel
cap open can cause the? lamp to
illuminate.
More information can be found in the
“Practical hints” section (
page 205).
!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. Noti-
fy an authorized Mercedes-Benz Center
immediately. Do not add brake fluid as
this will not solve the problem. For
more information, (
page 204).
Page 173 of 314
173 Operation
At the gas station
Coolant
For normal replenishing, use water (pota-
ble water quality). More information on
coolant can be found in the “Operation”
section (
page 180).
Exterior lamp switch (
page 83).Vehicle lighting
Check function and cleanliness. For infor-
mation on replacing light bulbs, see “Prac-
tical hints” section (
page 226).
Exterior lamp switch (page 83).
Tire inflation pressure
More information on tire inflation pressure
can be found in the “Operation” section
(
page 186).
Page 175 of 314

175 Operation
Engine compartment
Closing
Let the hood drop from a height of ap-
proximately 1ft (30cm).
The hood will lock audibly.
Make sure the hood is fully closed.
If you can raise the hood at a point
above the headlamps, then it is not
properly closed. Open it again and let it
drop with somewhat greater force.
Engine oil
The amount of oil your engine needs will
depend on a number of factors, including
driving style. Higher oil consumption can
occur when
the vehicle is new
the vehicle is driven frequently at
higher engine speeds
Engine oil consumption checks should only
be made after the vehicle break-in period.
Warning!
G
If you see flames or smoke coming from the
engine compartment, or if the coolant tem-
perature gauge indicates that the engine is
overheated, do not open the hood. Move
away from vehicle and do not open the hood
until the engine has cooled down. If neces-
sary, call the fire department.Warning!
G
The engine is equipped with a transistorized
ignition system. Because of the high voltage
it is dangerous to touch any components (ig-
nition coils, spark plug sockets, diagnostic
socket) of the ignition system
with the engine running
while starting the engine
if ignition is “on” and the engine is
turned manually
Warning!
G
Be careful that you do not close the hood on
anyone.
iDo not use any special lubricant addi-
tives, as these may damage the drive
assemblies. Using special additives not
approved by Mercedes-Benz will
restrict your warranty entitlement.
More information on this subject is
available at any authorized Mer-
cedes-Benz Center.
Page 180 of 314

180 OperationEngine compartmentBe careful not to spill any oil when adding.
Avoid environmental damage caused by oil
entering the ground or water.
Screw filler cap2 back on filler neck.
More information on engine oil can be
found in the “Technical data” section
(
page 277) and (
page 279).
Transmission fluid level
The transmission fluid level does not need
to be checked. If you notice transmission
fluid loss or gear shifting malfunctions,
have an authorized Mercedes-Benz Center
check the transmission.Coolant
The engine coolant is a mixture of water
and anticorrosion/antifreeze. To check
the coolant level, the vehicle must be
parked on level ground and the engine
must be cool.
The coolant expansion tank is located on
the passenger side of the engine compart-
ment.
!Excess oil must be siphoned or drained
off. It could cause damage to the
engine and catalytic converter not
covered by the Mercedes-Benz Limited
Warranty.
Warning!
G
In order to avoid any possibly serious burns:
Use extreme caution when opening the
hood if there are any signs of steam or
coolant leaking from the cooling system,
or if the coolant temperature gauge indi-
cates that the coolant is overheated.
Do not remove pressure cap on coolant
reservoir if engine temperature is above
194°F (90°C). Allow engine to cool
down before removing cap. The coolant
reservoir contains hot fluid and is under
pressure.
Using a rag, slowly open the cap approx-
imately ½ turn to relieve excess pres-
sure. If opened immediately, scalding
hot fluid and steam will be blown out un-
der pressure.
Do not spill antifreeze on hot engine
parts. Antifreeze contains ethylene gly-
col which may burn if it comes into con-
tact with hot engine parts.
Page 181 of 314
181 Operation
Engine compartment
SLK 230 Kompressor1Coolant expansion tank
2Float in the filler neck
Using a rag, turn the cap to the left to
the first detent position. Allow any ex-
cess pressure to escape.
Continue turning the cap to the left and
remove it.
The coolant level is correct if float2
can be seen at the top through the filler
neck.
Add coolant as required.
Turn the cap back, past the first detent
position, as far as it will go.
More information on coolant can be found
in the “Technical data” section
(
page 281).
SLK 320, SLK 32 AMG1Coolant expansion tank
2Marker in the filler neck
Using a rag, turn the cap slowly approx-
imately one half turn to the left to re-
lease any excess pressure.
Continue turning the cap to the left and
remove it.
iThe drain plugs for the cooling system
are located on the right side of the en-
gine block and at the bottom of the ra-
diator.
Page 182 of 314
182 OperationEngine compartment
The coolant level is correct if the level
for cold coolant: the level must
reach marker2 in the filler neck of
the expansion tank.
for warm coolant: is approx. 0.6 in
(1.5 cm) higher
Add coolant as required.
Replace and tighten cap.More information on coolant can be found
in the “Technical data” section
(
page 281).iThe drain plugs for the cooling system
are located on the right side of the en-
gine block and at the bottom of the ra-
diator.
Page 192 of 314

192 OperationVehicle care
Vehicle careCleaning and care of vehicle
In operation, your vehicle is subjected to
varying external influences which, if gone
unchecked, can attack the paintwork as
well as the underbody and cause lasting
damage.Such damage is caused not only by ex-
treme and varying climatic conditions, but
also by:
Air pollution
Road salt
Tar
Gravel and stone chipping
To avoid paint damage, you should imme-
diately remove:
Grease and oil
Fuel
Coolant
Brake fluid
Bird droppings
Insects
Tree resins, etc.
Frequent washing reduces and / or elimi-
nates the aggressiveness and potency of
the above adverse influences.More frequent washings are necessary to
deal with unfavorable conditions:
near the ocean
in industrial areas (smoke, exhaust
emissions)
during winter operation
You should check your vehicle from time to
time for stone chipping or other damage.
A n y d a m a g e s h o u l d b e r e p a i r e d a s s o o n a s
possible to prevent the start of corrosion.
In doing so, do not neglect the underbody
of the vehicle. A prerequisite for a thor-
ough check is a washing of the underbody
followed by a thorough inspection. Dam-
aged areas need to be re-undercoated.
Your vehicle has been treated at the facto-
ry with a wax-base rustproofing in the body
cavities which will last for the lifetime of
the vehicle. Post-production treatment is
neither necessary nor recommended by
Mercedes-Benz because of the possibility
of incompatibility between materials used
in the production process and others ap-
plied later.
Warning!
G
Many cleaning products can be hazardous.
Some are poisonous, others are flammable.
Always follow the instructions on the partic-
ular container. Always open your vehicle’s
doors or windows when cleaning the inside.
Never use fluids or solvents that are not de-
signed for cleaning your vehicle.
Page 207 of 314

207 Practical hints
What to do if …
Problem
Possible cause
Suggested solution
The fuel reserve and fuel cap placement
warning lamp:
lights up while driving
The fuel level has gone below the reserve
mark.
Refuel at the next gas station
(page 171).
blinks
The fuel cap is not closed tight.
Check the fuel cap.
A fuel system leak has been detected.
Have the fuel system checked as soon
as possible by an authorized
Mercedes-Benz Center
B
The yellow low engine coolant
level warning lamp remains lit af-
ter starting the engine or lights
up while driving.
The coolant level is too low.
Add coolant (
page 180).
If you have to add coolant frequently,
have the cooling system checked by
an authorized Mercedes-Benz Center.
Warning!
G
Do not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which
may burn if it comes into contact with hot
engine parts. You can be seriously burned.
!Do not ignore the low engine coolant
level warning light. Extended driving
with the light illuminated may cause
serious engine damage not covered by
the Mercedes-Benz Limited Warranty.
Do not drive without sufficient amount
of coolant in the cooling system. The
engine will overheat, causing major
engine damage.