2014 MERCEDES-BENZ CLA coolant temperature

Engine
ProblemPossible causes/consequences and
Solutions

The yellow Check
Engine warning lamp
lights up while the
engine is running.
There may be a malfunction, for example:
Rin the engine management
Rin the fuel injection system
Rin the exhaust system
Rin the ignition system
Rin the fuel system
The emission limit values may be exceeded and the enginemay
be running in emergency mode.
XHave the vehicle checked as soon as possible at a qualified
specialist workshop.
iIn some states, you must immediately visit a qualified
specialist workshop as soon as the yellow CheckEngine warning
lamp lights up.This depends on the locally applicable legal
requirements. If in doubt, check whether such legal regulations
apply in the state in which you are currently driving.


The yellow reserve fuel
warning lamp lights up
while the engine is
running.
The fuel level has dropped into the reserve range.
XRefuel at the nearest gas station.


The yellow reserve fuel
warning lamp flashes
while the engine is
running.
The fuel system pressure is too low. The fuel filler cap is not closed
correctly or the fuel system is leaking.
XCheck that the fuel filler cap is correctly closed.
XIf the fuel filler cap is not correctly closed:close the fuel filler
cap.
XIf the fuel filler cap is closed:visit a qualified specialist
workshop.
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The red coolant
warning lamp lights up
while the engine is
running and the coolant
temperature gage is at
the start of the scale.
The temperature sensor for the coolant temperature gage is
defective.
The coolant temperature is no longer being monitored. There is a
risk of engine damage if the coolant temperature is too high.
XPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions. Do not continue
driving under any circumstances.
XSecure the vehicle against rolling away (Ypage 153).
XConsult a qualified specialist workshop.
248Warning and indicator lamps in the instrument cluster
On-board computer and displays

ProblemPossible causes/consequences and
Solutions
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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.
XObserve the additional display messages in the multifunction
display.
XPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 153).
XLeave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
XCheck the coolant level and add coolant (Ypage 283). Observe
the warning notes.
XIf you need to add coolant more often than usual, have the
engine coolant system checked.
XMake sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.
XDo not start the engine again until the coolant temperature is
under 248‡(120 †). Otherwise, the engine could be damaged.
XDrive to the nearest qualified specialist workshop.
XAvoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic.
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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.
GWARNING
The engine is not being cooled sufficiently and may be damaged.
Do not drive whenyour engine is overheated. This can cause some
fluids which may have leaked into the engine compartment to
catch fire.
Vapor from the overheated engine can also cause serious burns
which can occur just by opening the hood.
There is a risk of injury.
XObserve the additional display messages in the multifunction
display.
XPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 153).
Warning and indicator lamps in the instrument cluster249
On-board computer and displays
Z

ProblemPossible causes/consequences and
Solutions
XLeave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
XCheck the coolant level and add coolant (Ypage 283). Observe
the warning notes.
XIf you need to add coolant more often than usual, have the
engine coolant system checked.
XMake sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.
XAt coolant temperatures under 248‡(120 †), drive to the next
qualified specialist workshop.
XAvoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic.
Driving systems
ProblemPossible causes/consequences and
Solutions

The red distance
warning lamp lights up
while the vehicle is in
motion.
The distance to the vehicle in front is too smallfor the speed
selected.
XIncrease the distance.

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.
XBe prepared to brake immediately.
XPay careful attention to the traffic situation. You may have to
brake or take evasive action.
For further information about the distance warning function of
COLLISION PREVENTION ASSIST (Ypage 62).
For further information about COLLISION PREVENTION ASSIST
PLUS (Ypage 64).
250Warning and indicator lamps in the instrument cluster
On-board computer and displays

Checking and adding other service
products
Checking coolantlevel
GWARNING
The engine cooling system is pressurized,
particularly when the engine is warm. When
opening the cap, you could be scalded by hot
coolant 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.
!The coolant may only be checked and
corrected when the engine is cool (coolant
temperature below 104 ‡ (40 †).
Checking the coolant when the coolant
temperature is above 104 ‡ (40 †) may
result in damage to the engine or to the
engine cooling system.
Example
XPark the vehicle on a level surface.
Only check the coolant level when the
vehicle is on a level surface and the engine
has cooled down.
XTurn the SmartKey to position2in the
ignition lock (Ypage 137).
XCheck the coolant temperature display in
the instrument cluster.
The coolant temperature must be below
104 ‡ (40 †).
XTurn the SmartKey to position
0(Ypage 137) in the ignition lock.
XSlowly turn caphalf a turn counter-
clockwise to allow excess pressure to
escape.
XTurn capfurther counter-clockwise and
remove it.
If the coolant is at the level of marker bar
"in the filler neck when cold, there is
enough coolant in coolant expansion
tank.
XIf necessary, add coolant that has been
tested and approved by Mercedes-Benz.
XReplace capand turn it clockwise as far
as it will go.
For further information on coolant, see
(Ypage 349).
Adding washer fluid to the windshield
washer system/headlampcleaning
system
GWARNING
Windshield washer concentrate is highly
flammable. If it comes into contact with hot
engine components or the exhaust systemit
could ignite. There is a riskoffire and injury.
Make sure that no windshield washer
concentrate is spilled next to the filler neck.
Example
XTo open:pull capupwards by the tab.
XAdd the premixed washer fluid.
XTo close:press caponto the filler neck
until it engages.
Engine compartment283
Maintenance and care
Z

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
(Ypage 345).
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
workshop or on the Internet at
http://bevo.mercedes-benz.com.
iHave the brake fluid renewed regularly at
a qualified specialist workshop.
Coolant
Important safety notes
GWARNING
If antifreeze comes into contact with hot
components in the engine compartment, it
may ignite. There is a risk of fire and injury.
Let the engine cool down before you add
antifreeze. 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 antifreezeprotection. You
could otherwise damage the engine.
Further information on coolants can be
found in the Mercedes-Benz Specifications
for Service Products, MB Specifications for
Service Products 310.1, e.g. on the
Internet at
http://bevo.mercedes-benz.com. Or
contact 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.
When handling coolant, observe the
important safety notes on service products
(Ypage 345).
The coolant is a mixture of water and
antifreeze/corrosion inhibitor. It performs
the following tasks:
Rcorrosionprotection
Rantifreeze protection
Rraising the boiling point
If the coolant has antifreeze protection down
to -35 ‡ (-37†),the boiling point of the
coolant during operationis approximately
266 ‡ (130 †).
The antifreeze/corrosion inhibitor
concentration in the engine cooling system
should:
Rbe at least 50%. This will protect the engine
cooling system against freezing down to
approximately -35 ‡ (-37 †).
Rnot exceed 55% (antifreeze protection
down to -49 ‡ [-45 †]). Otherwise, heat
will not be dissipated as effectively.
If the vehicle has lost coolant, add equal
amounts of water and antifreeze/corrosion
inhibitor.
Mercedes-Benz recommends an antifreeze/
corrosion inhibitor concentrate in
accordance with MB Specifications for
Service Products 310.1.
The coolant is checked with every
maintenance interval at a qualified specialist
workshop.
iWhen the vehicle is first delivered, it is
filled with a coolant mixture that ensures
adequate antifreeze and corrosion
protection.
Service products and filling capacities349
Technical data
Z