Page 170 of 304

170 OperationAt the gas station
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 trip1Windshield washer and headlamp 
cleaning system*
More information on filling up the res-
ervoir can be found in the “Operation” 
section (
page 179).
2Brake fluid
More information on brake fluid can be 
found in the “Technical data” section 
(
page 271).
3Coolant level
More information on coolant can be 
found in the “Operation” section 
(page 176).
4Engine oil level
More information on engine oil can be 
found in the “Operation” section 
(page 172).
Opening hood (
page 171).Coolant
For normal replenishing, use water (pota-
ble water quality). More information on 
coolant can be found in the “Operation” 
section (
page 176).
Exterior lamp switch (
page 83).
Vehicle lighting
Check function and cleanliness. For more 
information on replacing light bulbs, refer 
to page (
page 221) in the “Practical 
hints” section.
Exterior lamp switch (
page 83).
Tire inflation pressure
More information on tire inflation pressure 
can be found in the “Operation” section 
(
page 181).
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 199). 
     
        
        Page 172 of 304

172 OperationEngine compartment
Closing
Let the hood drop from a height of ap-
proximately 1ft (30cm).
The hood will lock audibly.
Check to make sure that 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 high-
er engine speeds
Engine oil consumption checks should only 
be made after the vehicle break-in period.
Checking engine oil level
When checking the oil level the vehicle 
must
be parked on level ground
be at normal operating temperature
have been stationary for at least five 
minutes with the engine turned off
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. If necessary, 
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. 
     
        
        Page 176 of 304

176 OperationEngine compartmentTransmission 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. 
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.
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 177 of 304

177 Operation
Engine compartment
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 273).
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.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 273).
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.
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 187 of 304

187 Operation
Vehicle care
Vehicle care
Cleaning 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 chippingTo avoid paint damage, you should imme-
diately remove:
Grease and oil
Fuel
Coolant
Brake fluid
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. 
Any damage should be repaired as soon as 
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.
We have selected car-care products and 
compiled recommendations which are 
specially matched to our vehicles and 
which always reflect the latest technology. 
You can obtain Mercedes-Benz approved 
car-care products at your authorized 
Mercedes-Benz Center.
Scratches, corrosive deposits, corrosion or 
damage due to negligent or incorrect care 
cannot always be removed or repaired with 
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 201 of 304

201 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 169).
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 176).
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. 
     
        
        Page 255 of 304
255 Technical data
Spare parts service
Warranty coverage
Identification labels
Layout of poly-V-belt drive
Engine
Rims and Tires
Electrical system
Main Dimensions
Weights
Fuels, coolants, lubricants etc.
Consumer information 
     
        
        Page 259 of 304
259 Technical data
Layout of poly-V-belt drive
Layout of poly-V-belt drive
SLK 230 KompressorThe SLK 230 Kompressor has two 
poly-V-belts.1Coolant pump
2Idler pulley
3Power steering pump
4Air conditioner compressor
5Crankshaft
6Idler pulley
7Generator (alternator)
8Supercharger
SLK 320
1Idler pulley
2Automatic belt tensioner
3Power steering pump
4Air conditioner compressor
5Crankshaft
6Coolant pump
7Generator (alternator)
SLK 32 AMG
1Idler pulley
2Idler pulley
3Supercharger
4Automatic belt tensioner
5Power steering pump
6Air conditioner compressor
7Crankshaft
8Coolant pump
9Generator (alternator)