Page 358 of 506

357 Practical hints
What to do if …?
Problem
Possible cause
Suggested solution
•
The red coolant warning lamp
comes on when the engine is
running.
There is insufficient coolant in the reservoir.
Add coolant to prevent engine from
overheating (
page 310).
If this warning lamp comes on frequently,
there is a leak in the cooling system.
Have the cooling system checked.
If the coolant level is correct, the electric ra-
diator fan may be broken.
If the coolant temperature is below
257 °F (125 °C), you can continue
driving to the nearest authorized
Mercedes-Benz Center.
Avoid high engine loads (e.g. driving
uphill) and stop-and-go driving.
•
The red coolant warning lamp
comes on while driving and you
hear a warning sound.
The coolant temperature has exceeded
257 °F (125 °C).
Stop as soon as possible and allow
the engine and coolant to cool down.
Warning!
G
Driving when your engine is badly overheat-
ed can cause some fluids which may have
leaked into the engine compartment to
catch fire. You could be seriously burned.
Steam from an overheated engine can cause
serious burns and can occur just by opening
the hood. Stay away from the engine if you
see or hear steam coming from it.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until the
engine has cooled down.
Page 378 of 506

377 Practical hints
What to do if …?
During severe operating conditions and
stop-and-go city traffic, the coolant tem-
perature may rise close to 248°F (120°C).
Display symbol
Display message
Possible cause
Possible solution
•
Coolant
Stop, engine off!
The coolant is too hot.
Stop the vehicle and turn off the en-
gine.
Only start the engine again after the
message disappears. You could other-
wise damage the engine.
Warning!
G
Driving when your engine is badly overheat-
ed can cause some fluids which may have
leaked into the engine compartment to
catch fire. You could be seriously burned.
Steam from an overheated engine can cause
serious burns and can occur just by opening
the hood. Stay away from the engine if you
see or hear steam coming from it.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until the
engine has cooled down.
!The engine should not be operated with
the coolant temperature above 248°F
(120°C). Doing so may cause serious
engine damage which is not covered by
the Mercedes-Benz Limited Warranty.
Page 379 of 506
378 Practical hintsWhat to do if …?Display symbol
Display message
Possible cause
Possible solution
•
Coolant
Stop, engine off!
The poly-V-belt could be broken.
Stop immediately and check the
poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise
the engine will overheat due to an in-
operative water pump which may re-
sult in damage to the engine. Notify an
authorized Mercedes-Benz Center.
If it is intact:
Do not continue to drive the vehicle
with this message displayed. Doing so
could result in serious engine damage
that is not covered by the
Mercedes-Benz Limited Warranty.
Drive immediately to the nearest au-
thorized Mercedes-Benz Center.
Coolant
Visit workshop
!
The cooling fan for the coolant is malfunc-
tioning.
Observe the coolant temperature dis-
play.
Have the fan replaced as soon as pos-
sible.
Page 380 of 506
379 Practical hints
What to do if …?
Display symbol
Display message
Possible cause
Possible solution
G
Display malfunction
Visit workshop
The instrument cluster display is malfunc-
tioning.
Continue driving with added caution.
Visit an authorized Mercedes-Benz
Center as soon as possible.
The displays for several systems have
malfunctioned. Some systems them-
selves may also have malfunctioned.
Have the electronic systems checked
by an authorized Mercedes-Benz Cen-
ter.
±
Display defective
Visit workshop!
Certain electronic systems are unable to
relay information to the control system.
The following systems may have failed:
Coolant temperature display
Tachometer
Cruise control display
Have the electronic systems checked
by an authorized Mercedes-Benz Cen-
ter.
J
Doors open!
You are attempting to drive with one or
more doors open.
Close the doors.
Page 454 of 506
453 Technical data
Fuels, coolants, lubricants, etc.
Fuels, coolants, lubricants, etc.
CapacitiesVehicle components and their respective
lubricants must match. Therefore only use
products tested and approved by
Mercedes-Benz.Please refer to the Factory Approved Ser-
vice Products pamphlet, or inquire at your
Mercedes-Benz Center.
Model
Capacity
Fuels, coolants, lubricants, etc.
Engine with oil filter
CLK 320
CLK 500
CLK 55 AMG
8.5 US qt (8.0 l)
7.5 US qt (7.0 l)
9.0 US qt (8.5 l)
Approved engine oils
Automatic transmission
CLK 320
CLK 500
CLK 55 AMG
8.0 US qt (7.5 l)
9.3 US qt (8.7 l)
9.3 US qt (8.7 l)
MB Automatic Transmission Fluid
Rear axle
CLK 320
CLK 500
CLK 55 AMG
1.28 US qt (1.2 l)
1.5 US qt (1.4 l)
1.5 US qt (1.4 l)
Hypoid gear oil SAE 85 W 90
Power steering
approx. 1.1 US qt (1.0 l)
MB Power Steering Fluid (Pentosin
CHF 11S)
Front wheel hubs
approx. 3.0 oz (85 g) each
High temperature roller bearing grease
Brake system
0.64 US qt (0.6 l)
MB Brake Fluid (DOT 4+)
Page 455 of 506
454 Technical dataFuels, coolants, lubricants, etc.
Model
Capacity
Fuels, coolants, lubricants, etc.
Cooling system
CLK 320
CLK 500
CLK 55 AMG
approx. 10.7 US qt (10.0 l)
approx. 12.8 US qt (12.0 l)
approx. 12.8 US qt (12.0 l)
MB 325.0 Anticorrosion/Antifreeze
Agent
Fuel tank
including a reserve of
CLK 320
CLK 500
CLK 55 AMG
16.35 US gal (62.0 l)
2.11 US gal (8.0 l)
2.11 US gal (8.0 l)
2.64 US gal (10.0 l)
Premium unleaded gasoline:
Minimum Posted Octane 91
(Avg. of 96 RON / 86 MON)
Air conditioning system
R-134a refrigerant and special PAG lu-
bricant oil (never R-12)
Windshield washer and
headlamp cleaning system*
6.4 US qt (6.0 l)
MB Windshield Washer Concentrate
1
1Use MB Windshield Washer Concentrate “S” and water for temperatures above freezing point or MB Windshield Washer Concentrate “S” and commercially available
premixed windshield washer solvent / antifreeze for temperatures below freezing point. Follow suggested mixing ratios (page 460).
Page 461 of 506

460 Technical dataFuels, coolants, lubricants, etc.Windshield washer system and headlamp cleaning system*
Both the windshield washer and headlamp
cleaning system are supplied from the
windshield washer fluid reservoir.
The washer fluid reservoir has a capacity of
approx. 6.4 US qt (6.0 l).
Refill the reservoir with MB Windshield
Washer Concentrate “S” and water (or
concentrate and commercially avail-
able premixed windshield washer
solvent / antifreeze, depending on
ambient temperatures).Windshield and headlamp washer fluid
mixing ratio
For temperatures above freezing point, use
MB Windshield Washer Concentrate “S”
and water:
1 part “S” to 100 parts water
(1.34 fl oz [40 ml] “S” to 1 gallon [4.0 l]
water)
For temperatures below freezing point, use
MB Windshield Washer Concentrate “S”
and commercially available premixed
windshield washer solvent / antifreeze:
1 part “S” to 100 parts solvent
(1.34 fl oz [40 ml] “S” to 1 gallon [4.0 l]
solvent)
Warning!
G
Washer solvent/antifreeze is highly flam-
mable. Do not spill washer
solvent/antifreeze on hot engine parts, be-
cause it may ignite and burn. You could be
seriously burned.
Page 464 of 506

463 Technical terms
Head-thorax air bag
Installed in the driver and the front pas-
senger seat, these air bags protect oc-
cupants during side impact collisions
exceeding a preset threshold. Unlike
normal side impact air bags,
head-thorax air bags are also designed
to provide protection for the head area.
Instrument cluster
The displays and indicator/warning
lamps in the driver’s field of vision, in-
cluding the tachometer, speedometer,
coolant temperature indicator and fuel
display.
KEYLESS-GO*
System for entering and operating the
vehicle without the use of a SmartKey.
Kickdown
Depressing the accelerator past the
point of resistance shifts the transmis-
sion down to the lowest possible gear.
This very quickly accelerates the vehi-
cle and should not be used for normal
acceleration needs.Kilopascal (kPa)
(
page 336)
Lock button
Button on the door which indicates
whether the door is locked or un-
locked. Pushing the lock button down
on an individual door from inside will
lock that door.
Maintenance System (U.S. vehicles)
Maintenance service indicator in the
multifunction display that informs the
driver when the next vehicle mainte-
nance service is due. The Maintenance
System in your vehicle tracks distance
driven and the time elapsed since your
last maintenance service, and calls for
the next maintenance service
accordingly.
Maximum load rating
(page 337)
Maximum loaded vehicle weight
(page 337)
Maximum tire inflation pressure
(page 337)Memory function*
Used to store three individual seat,
steering wheel and mirror positions for
each SmartKey or, if so equipped,
KEYLESS-GO* feature.
Menu
The control system displays are ar-
ranged in menus. Each menu contains
a number of commands for particular
systems.
MON
(M
otor O
ctane N
umber)
The Motor Octane Number for gasoline
as determined by a standardized meth-
od. It is an indication of a gasoline's
ability to resist undesired detonation
(knocking). The average of both the
MON (Motor Octane Number) and
->RON (Research Octane Number) is
posted at the pump, also known as
ANTI-KNOCK INDEX.
Multifunction display
Display field in the speedometer used
to present information provided by the
control system.