2015 MERCEDES-BENZ C-Class SEDAN coolant temperature

Warning/
indicator
lamp
0051
0051 Signal type
Possible causes/consequences and 0050 0050Solutions 00AC
0051
The red coolant warning lamp comes on while the engine is running.
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator may be blocked
or the electric engine radiator fan may be malfunctioning.
The coolant is too hot and the engine is no longer being cooled sufficiently.
X Observe the additional display messages in the multifunction display.
X Pull over and stop the vehicle safely and switch off the engine, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 174).
X Leave the vehicle and keep a safe distance from the vehicle until the engine
has cooled down.
X Check the coolant level and add coolant, observing the warning notes
(Y page 327).
X If you need to add coolant more often than usual, have the engine coolant
system checked.
X Make sure that the air supply to the engine radiator is not blocked, e.g. by
snow, slush or ice.
X Do not start the engine again until the coolant temperature is below 248 ‡
(120 †). Otherwise, the engine could be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in mountainous
terrain, and stop-and-go traffic. 00AC
0051
The red coolant warning lamp comes on while the engine is running. A
warning tone also sounds.
The coolant temperature has exceeded 248 ‡ (120 †). The airflow to the
engine radiator may be blocked or the coolant level may be too low.
G WARNING
The engine is not being cooled sufficiently and may be damaged.
Do not drive when your engine is overheated. This can cause some fluids which may have leaked into the engine compartment to catch fire.
Steam from the overheated engine can also cause serious burns which can
occur just by opening the hood.
There is a risk of injury.
X Observe the additional display messages in the multifunction display.
X Pull over and stop the vehicle safely and switch off the engine, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 174).292
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Warning/
indicator
lamp
0051 0051
Signal type
Possible causes/consequences and 0050
0050Solutions X
Leave the vehicle and keep a safe distance from the vehicle until the engine
has cooled down.
X Check the coolant level and add coolant, observing the warning notes
(Y page 327).
X If you need to add coolant more often than usual, have the engine coolant
system checked.
X Make sure that the air supply to the engine radiator is not blocked, e.g. by
snow, slush or ice.
X At coolant temperatures below 248 ‡(120 †), drive to the nearest qualified
specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in mountainous
terrain, and stop-and-go traffic. Driving systems
Warning/
indicator
lamp
0051 0051
Signal type
Possible causes/consequences and 0050
0050Solutions 00BA
0051
The red distance warning lamp lights up while the vehicle is in motion. A
warning tone also sounds.
You are approaching a vehicle or a stationary obstacle in your line of travel at too high a speed.
X Be prepared to brake immediately.
X Pay careful attention to the traffic situation. You may have to brake or take
evasive action.
Further information on PRE ‑SAFE®
Brake (Y page 74).
For further information about the distance warning function of COLLISION
PREVENTION ASSIST PLUS, see (Y page 69). Warning and indicator lamps in the instrument cluster
293On-board computer and displays Z

X
Replace cap 0043on the filler neck and turn
clockwise.
Ensure that the cap locks into place
securely.
X Check the oil level again with the oil dip-
stick (Y page 325).
Further information on engine oil
(Y page 400). Additional service products
Checking coolant level G
WARNING
Certain components in the engine compart-
ment, such as the engine, radiator and parts
of the exhaust system, can become very hot.
Working in the engine compartment poses a
risk of injury.
Where possible, let the engine cool down and touch only the components described in the
following. G
WARNING
The engine cooling system is pressurized, par- ticularly when the engine is warm. When
opening the cap, you could be scalded by hotcoolant spraying out. There is a risk of injury.
Let the engine cool down before opening the
cap. Wear eye and hand protection when
opening the cap. Open the cap slowly half a
turn to allow pressure to escape. X
Park the vehicle on a level surface. Only check the coolant level when the vehi-
cle is on a level surface and the engine has
cooled down.
X Turn the SmartKey to position 2in the igni-
tion lock (Y page 157).
or
X On vehicles with KEYLESS-GO, press the
Start/Stop button twice (Y page 157).
X Check the coolant temperature display in
the instrument cluster.
The coolant temperature must be below
158 ‡ (70 †).
X Turn the SmartKey to position
0(Y page 157) in the ignition lock.
or
X On vehicles with KEYLESS-GO, pull the
Start/Stop button from the ignition lock
(Y page 157).
X Slowly turn cap 0043half a turn counter-
clockwise to allow excess pressure to
escape.
X Turn cap 0043further counter-clockwise and
remove it.
If the coolant is at the level of marker bar 0087
in the filler neck when cold, there is enough coolant in coolant expansion tank 0044.
If the coolant level is approximately 0.6 in
(1.5 cm) above marker bar 0087in the filler
neck when warm, there is enough coolant
in expansion tank 0044.
X If necessary, add coolant that has been tes-
ted and approved by Mercedes-Benz.
X Replace cap 0043and turn it clockwise as far
as it will go.
For further information on coolant, see
(Y page 401).
Adding washer fluid to the windshield
washer system G
WARNING
Certain components in the engine compart-
ment, such as the engine, radiator and parts
of the exhaust system, can become very hot. Engine compartment
327Maintenance and care
Z

Brake fluid
G
WARNING
The brake fluid constantly absorbs moisture
from the air. This lowers the boiling point of
the brake fluid. If the boiling point of the brake fluid is too low, vapor pockets may form in the brake system when the brakes are applied
hard. This would impair braking efficiency.
There is a risk of an accident.
You should have the brake fluid renewed at
the specified intervals.
When handling brake fluid, observe the
important safety notes on service products
(Y page 397).
The brake fluid change intervals can be found
in the Maintenance Booklet.
Only use brake fluid approved by Mercedes-
Benz according to MB Approval 331.0.
Information about approved brake fluid can
be obtained at any qualified specialist work-
shop or on the Internet at
http://bevo.mercedes-benz.co m.
i Have the brake fluid regularly replaced at
a qualified specialist workshop and the
replacement confirmed in the Maintenance Booklet. Coolant
Important safety notes G
WARNING
If antifreeze comes into contact with hot com- ponents in the engine compartment, it may
ignite. There is a risk of fire and injury.
Let the engine cool down before you add anti-
freeze. Make sure that antifreeze is not spilled
next to the filler neck. Thoroughly clean the
antifreeze from components before starting
the engine.
! Only add coolant that has been premixed
with the desired antifreeze protection. You
could otherwise damage the engine. Further information on coolants can be
found in the Mercedes-Benz Specifications
for Service Products, MB BeVo 310.1, e.g.
on the Internet at
http://bevo.mercedes-benz.com. Or con-
tact a qualified specialist workshop.
! Always use a suitable coolant mixture,
even in countries where high temperatures prevail.
Otherwise, the engine cooling system is not
sufficiently protected from corrosion and
overheating.
i Have the coolant regularly replaced at a
qualified specialist workshop and the
replacement confirmed in the Maintenance Booklet.
The coolant is a mixture of water and anti-
freeze/corrosion inhibitor. It performs the
following tasks:
R corrosion protection
R antifreeze protection
R raising the boiling point
If the coolant has antifreeze protection down to -35 ‡(-37 †), the boiling point of the cool-
ant during operation is approximately 266 ‡
(130 †).
The antifreeze/corrosion inhibitor concentra- tion in the engine cooling system should:
R be at least 50%. This will protect the engine
cooling system against freezing down to
approximately -35 ‡ (-37 †).
R no t exceed 55% (antifreeze protection
down to -49 ‡ [-45 †]). Otherwise, heat
will not be dissipated as effectively.
Mercedes-Benz recommends an antifreeze/
corrosion inhibitor concentrate in accord-
ance with MB Specifications for Service Prod- ucts 310.1.
The coolant is checked with every mainte-
nance interval at a qualified specialist work-
shop.
i When the vehicle is first delivered, it is fil-
led with a coolant mixture that ensures Service products and filling capacities
401Technical data Z

adequate antifreeze and corrosion protec-
tion.
i The coolant is checked with every main-
tenance interval at a qualified specialist
workshop.
Filling capacities Model Capacity
C 300
C 300 4MATIC
8.5 US qt (8.0 l)
C 400 4MATIC
11.5 US qt (10.9 l)
i
Use MB 325.0 or MB 326.0 corrosion
inhibitor/antifreeze. Windshield/headlamp cleaning sys-
tem
Important safety notes G
WARNING
Windshield washer concentrate could ignite if it comes into contact with hot engine compo-
nents or the exhaust system. There is a risk of
fire and injury.
Make sure that no windshield washer con-
centrate is spilled next to the filler neck.
! Only use washer fluid that is suitable for
plastic lamp lenses, e.g. MB SummerFit or
MB WinterFit. Unsuitable washer fluid
could damage the plastic lenses of the
headlamps.
! Do not add distilled or de-ionized water to
the washer fluid container. Otherwise, the
level sensor may be damaged.
! Only MB SummerFit and MB WinterFit
washer fluid should be mixed together. The spray nozzles may otherwise become
blocked. At temperatures above freezing:
X Fill the washer fluid reservoir with a mixture
of water and windshield washer fluid, e.g.
MB SummerFit.
Add 1 part MB SummerFit to 100 parts water.
At temperatures below freezing:
X Fill the washer fluid reservoir with a mixture
of water and washer fluid, e.g. MB Winter-
Fit.
For the correct mixing ratio refer to the
information on the antifreeze reservoir.
i Add windshield washer fluid, e.g. MB
SummerFit or MB WinterFit, to the washer
fluid all year round. Climate control system refrigerant
Important safety notes The climate control system of your vehicle is
filled with refrigerant R‑
134a.
The instruction label regarding the refrigerant type used can be found on the radiator cross
member.
! Only the refrigerant R‑134a and the PAG
oil approved by Mercedes-Benz may be
used. The approved PAG oil may not be
mixed with any other PAG oil that is not
approved for R-134a refrigerant. Other-
wise, the climate control system may be
damaged.
Service work, such as topping up refrigerant
or replacing components, may only be carried out by a qualified specialist workshop. All
applicable regulations must be adhered to,
SAE standard J639 included.
Always have work on the climate control sys-
tem carried out at a qualified specialist work-
shop. 402
Service products and filling capacitiesTechnical data