Page 289 of 464

289 Operation
Engine compartment
Checking engine oil level with the
control system, SLK 55 AMG
When checking the oil level
the vehicle must be parked on level
ground.
with the engine at operating tempera-
ture, the vehicle must have been sta-
tionary for at least five minutes with
the engine turned off.
with the engine not at operating tem-
perature, the vehicle must have been
stationary for at least 30 minutes with
the engine turned off.
To check the engine oil level via the
multifunction display, do the following:
Switch on the ignition (
page 35).
The standard display appears in the
multifunction display (
page 122).
Press buttonk orj on the mul-
tifunction steering wheel repeatedly
until the following message appears in
the multifunction display (
page 118):
One of the following messages will
subsequently appear in the multifunc-
tion display:
Engine oil level
ok
Add 1.0 qt.
(Canada:
1.0 liter
)
to reach max. oil level
Add 1.5 qts.
(Canada:
1.5 liters
)
to reach max. oil level
Add 2.0 qts.
(Canada:
2.0 liters
)
to reach max. oil level
If necessary, add engine oil.
For adding engine oil, see “Adding en-
gine oil” (
page 292).
For more information on engine oil, see
“Fuels, coolants, lubricants, etc.”
(
page 422).iIf you want to interrupt the checking
procedure, press buttonk orj
on the multifunction steering wheel
(page 118).
Page 290 of 464

290 OperationEngine compartmentOther display messages
If the ignition is not switched on, the fol-
lowing message will appear:Turn on ignition
to see engine oil level
Switch on the ignition (
page 35).
If you see the message:
Observe waiting time
If engine is at operating temperature,
wait five minutes before repeating
check procedure.
If engine is not at operating tempera-
ture yet, you must wait 30 minutes
before checking oil.If you see the message:
Engine oil level
Not when engine on
Turn off the engine.
If the engine is at operating tempera-
ture, wait five minutes before checking
oil.
If the engine is not at operating
temperature yet, you must wait
30 minutes before checking oil.If there is excess engine oil with the engine
at normal operating temperature, the
following message will appear:
Engine oil level
Reduce oil level
Have excess oil siphoned or drained
off. Contact an authorized
Mercedes-Benz Center.
For more information on messages in the
display concerning engine oil, see the
“Practical hints” section (
page 348).
iIf you want to interrupt the checking
procedure, press buttonk orj
on the multifunction steering wheel
(page 118).
!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.
Page 291 of 464

291 Operation
Engine compartment
Checking engine oil level with the oil
dipstick, SLK 350
When checking the oil level
the vehicle must be parked on level
ground.
with the engine at operating tempera-
ture, the vehicle must have been sta-
tionary for at least five minutes with
the engine turned off.
with the engine not at operating tem-
perature, the vehicle must have been
stationary for at least 30 minutes with
the engine turned off.1Oil dipstick
2Upper (max) mark
3Lower (min) mark
To check the engine oil level with the oil
dipstick, do the following:
Open the hood (
page 287).
Pull out oil dipstick1.
Wipe oil dipstick1 clean.
Fully insert oil dipstick1 into the
dipstick guide tube.
Pull out oil dipstick1 again after
approximately three seconds to obtain
accurate reading.
The oil level is correct when it is be-
tween the lower (min) mark3 and
upper (max) mark2 of oil dipstick1.
If necessary, add engine oil.
For adding engine oil, see “Adding en-
gine oil” (
page 292).
For more information on engine oil, see
“Fuels, coolants, lubricants, etc.”
(
page 422).
For more information on messages in the
multifunction display concerning engine
oil, see the “Practical hints” section
(page 348).iThe filling quantity between the upper
and lower marks on the oil dipstick is
approximately 2.1 US qt. (2.0 l).
Page 292 of 464

292 OperationEngine compartmentAdding engine oil
Only use approved engine oils and oil fil-
ters required for vehicles with Mainte-
nance System (U.S. vehicles) or FSS
(Canada vehicles). For a listing of approved
engine oils and oil filters, refer to the Fac-
tory Approved Service Products pamphlet
in your vehicle literature portfolio, or con-
tact an authorized Mercedes-Benz Center.
Using engine oils and oil filters of specifica-
tion other than those expressly required
for the Maintenance System (U.S. vehi-
cles) or FSS (Canada vehicles), or changing
of oil and oil filter at change intervals long-
er than those called for by the Mainte-
nance System (U.S. vehicles) or FSS
(Canada vehicles) will result in engine dam-
age not covered by the Mercedes-Benz
Limited Warranty.
SLK 3501Filler capSLK 55 AMG1Filler cap
Unscrew filler cap1 from filler neck.
Add engine oil as required.
Be careful not to overfill with oil.
Be careful not to spill any oil when adding.
Avoid environmental damage caused by oil
entering the ground or water.
Screw filler cap1 back on filler neck.
For more information on engine oil, see the
“Technical data” section (
page 422) and
(
page 424).!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.
Page 293 of 464

293 Operation
Engine compartment
Transmission fluid level*
Vehicles with automatic transmission*:
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 level
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.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 coolant temperature is
above 158°F (70°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
glycol which may burn if it comes into
contact with hot engine parts.
Page 294 of 464

294 OperationEngine compartmentThe coolant expansion tank is located on
the passenger side of the engine compart-
ment.SLK 350 (example)1Coolant expansion tank
2Cap
3Marking bar in the expansion tank
Using a rag, turn cap2 slowly approx-
imately one half turn counterclockwise
to release any excess pressure.
Continue turning cap2 counterclock-
wise and remove it.
The coolant level is correct if the level
for cold coolant: reaches marking
bar3 in expansion tank1
for warm coolant: is approximately
0.6 in (1.5 cm) higher
Add coolant as required.
Replace and tighten cap2.
For more information on coolant, see
“Coolants” (
page 426).
Battery
Your vehicle’s battery is located in the en-
gine compartment.
The battery should always be sufficiently
charged in order to achieve its rated ser-
vice life. Refer to the Maintenance Booklet
for battery maintenance intervals.
If you use your vehicle mostly for
short-distance trips, you will need to have
the battery charge checked more frequent-
ly.
When replacing the battery, always use
batteries approved by Mercedes-Benz.
If you do not intend to operate your vehicle
for an extended period of time, consult an
authorized Mercedes-Benz Center about
steps you need to observe.
Page 295 of 464

295 Operation
Engine compartment
Batteries contain materials that can harm
the environment if disposed of improperly.
Recycling of batteries is the preferred
method of disposal. Many states require
sellers of batteries to accept old batteries
for recycling.Windshield washer system and
headlamp cleaning system*
The windshield washer reservoir is located
on the passenger side of the engine com-
partment.SLK 350 (example)1Washer fluid reservoir cap
Fluid for the windshield washer system and
the headlamp cleaning system* is supplied
from the windshield washer reservoir. It
has a capacity of approx. 7.4 US qt (7 l).
G
Observe all safety instructions
and precautions when handling
automotive batteries.
A
Risk of explosion
D
Keep flames or sparks away
from battery. Do not smoke.
B
Battery acid is caustic. Do not
allow it to come into contact
with skin, eyes or clothing.
In case it does, immediately
flush affected area with clean
water and seek medical help if
necessary.
E
Wear eye protection.
C
Keep children away.
F
Follow the instructions in this
Operator's Manual.
Page 296 of 464

296 OperationEngine compartmentDuring all seasons, add MB Windshield
Washer Concentrate “S” to water. Premix
the windshield washer fluid in a suitable
container.
Pull cap upward using latch until it
opens.
Refill the reservoir with MB Windshield
Washer Concentrate and water (or
commercially available premixed wind-
shield washer solvent/antifreeze, de-
pending on ambient temperatures).
Always use washer solvent/antifreeze
where temperatures may fall below
freezing point. Failure to do so could re-
sult in damage to the washer sys-
tem/reservoir.
Push cap down until it engages.For more information, see “Windshield
washer system and headlamp cleaning
system*” (
page 429).
Warning!
G
Washer solvent/antifreeze is highly flamma-
ble. Do not spill washer solvent/antifreeze
on hot engine parts, because it may ignite
and burn. You could be seriously burned.!Only use washer fluid which is suitable
for plastic lenses. Improper washer flu-
id can damage the plastic lenses of the
headlamps.