2020 MERCEDES-BENZ METRIS engine coolant

Warning/
indicator
lamp
N Signal type
Possible causes/consequences and
M Solutions?
N 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 display messages.
X Stop the vehicle immediately, paying attention to road and traffic conditions,
and switch off the engine.
X Secure the vehicle to prevent it from rolling away (Y page 138).
X Exit 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

253).
X If you have to add coolant more frequently, have the engine cooling system
checked.
X Make sure that the air supply to the radiator is not obstructed, by frozen
slush for example.
X Check the coolant temperature:
R using the display in the on-board computer on vehicles without steering
wheel buttons ( Y page

178)
R using the analog display in the instrument cluster on vehicles with steering
wheel buttons ( Y page 40)
X Do not start the engine again until the coolant temperature is below the maxi-
mum value specified below. The engine could otherwise be damaged.
X Drive to the nearest qualified specialist workshop.
Avoid heavy loads on the engine, e.g. driving in mountainous terrain, and
stop-start traffic.
Under normal driving conditions and at the correct coolant level, the coolant
temperature display may rise to the letter H or to the red mark.?
N The red coolant warning lamp comes on while the engine is running. An addi-
tional warning tone sounds.
The coolant temperature has exceeded the maximum value specified below. 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 adequately and could become damaged.
Never drive with an overheated engine. Otherwise, fluids which may have leaked
into the engine compartment could catch fire.
In addition, steam from an overheated engine can cause serious burns, which
can occur just by opening the hood.
There is a risk of injury.
X Observe the display messages.
X Stop the vehicle immediately, paying attention to road and traffic conditions,
and switch off the engine. 234
Indicator and warning lamps in the instrument cluster
On-board computer and displays

Warning/
indicator
lamp
N Signal type
Possible causes/consequences and
M SolutionsX
Secure the vehicle to prevent it from rolling away ( Y page 138).
X Exit 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
253).
X If you have to add coolant more frequently, have the engine cooling system
checked.
X Make sure that the air supply to the radiator is not obstructed, by frozen
slush for example.
X Check the coolant temperature:
R using the display in the on-board computer on vehicles without steering
wheel buttons ( Y page

178)
R using the analog display in the instrument cluster on vehicles with steering
wheel buttons ( Y page 40)
X If the coolant temperature is below the maximum value specified below, you
can continue driving to the nearest qualified specialist workshop.
Avoid heavy loads on the engine, e.g. driving in mountainous terrain, and
stop-start traffic.
Under normal driving conditions and at the correct coolant level, the coolant
temperature display may rise to the letter H or to the red mark.Driving systems
Warning/
indicator
lamp
N Signal type
Possible causes/consequences and
M Solutions·
N The red distance warning lamp lights up while the vehicle is in motion.
The distance to the vehicle in front is too small for the speed selected.
X Increase the distance. ·
N The red distance warning lamp lights up while the vehicle is in motion. An
additional warning tone 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 particular attention to the traffic situation. You may have to brake or take
evasive action.
Further information about the distance warning function can be found under
"COLLISION PREVENTION ASSIST"
(Y page 149). Indicator and warning lamps in the instrument cluster
235
On-board computer and displays Z

Useful information
This Operator's Manual describes all models
as well as standard and optional equipment of
your vehicle that were available at the time of
going to print. Country-specific variations are
possible. Note that your vehicle may not be
equipped with all of the described functions.
This also applies to systems and functions rel-
evant to safety.
Read the information on qualified specialist
workshops (Y page
32).Engine compartment
Hood
Important safety notes G
WARNING
If the hood is unlatched, it may open up
when the vehicle is in motion and block your
view. There is a risk of an accident.
Never unlatch the hood while driving. Before
every trip, ensure that the hood is locked. G
WARNING
Opening the hood when the engine is over-
heated or when there is a fire in the engine
compartment could expose you to hot gases
or other service products. There is a risk of
injury.
Let an overheated engine cool down before
opening the hood. If there is a fire in the
engine compartment, keep the hood closed
and contact the fire department. G
WARNING
The engine compartment contains moving
components. Certain components, such as
the radiator fan, may continue to run or start
again suddenly when the ignition is off.
There is a risk of injury. If you need to do any work inside the engine
compartment:
R switch off the ignition
R never reach into the area where there is a
risk of danger from moving components,
such as the fan rotation area
R remove jewelry and watches
R keep items of clothing and hair, for exam-
ple, away from moving parts G
WARNING
The ignition system operates with a high
voltage. If you touch the live components,
you could receive an electric shock. There is
an increased risk of injury.
Never touch components of the ignition sys-
tem if:
R the engine is running or being started
R the key is in radio position or drive posi-
tion in the ignition lock
The live components of the ignition system
are, for example:
R ignition coils
R spark plug connectors
R diagnostic sockets 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.
If you have to carry out work in the engine
compartment, only touch the following compo-
nents:
R hood
R oil dipstick
R engine oil filler neck cap
R washer fluid reservoir cap
R coolant expansion tank cap250
Engine compartment
Maintenance and care

X
Hold support strut ? and lift the hood
slightly.
X Guide support strut ? towards retainer =
and apply slight pressure to make it engage.
X Lower the hood and allow it to fall with
momentum from a height of approximately
1 ft (30 cm
).
The hood locks audibly.
X Check that the hood is correctly locked.
If the hood can be raised slightly, it is not
properly engaged. If the hood is not cor-
rectly engaged, open the hood again. Let
the hood fall with a little more momentum. Overview of the engine compart-
ment
Engine compartment (example)
:
Engine oil filler neck cap (Y page
252)
; Brake fluid reservoir cap (Y page
255)
= Coolant expansion tank cap ( Y page
253)
? Washer fluid reservoir cap (Y page
256)
Regularly check the fluid level and the assem-
bly for leaks. If you detect fluid loss, e.g. oil
stains on the vehicle parking space, consult a
qualified specialist workshop immediately. Engine oil
General notes !
Engine oil gets dirty in the course of opera-
tion and its quality and volume are gradually
diminished. Regularly check the oil level,
and top up or have it replaced as needed.
Observe the information on approved engine
oils and oil consumption under "Service prod-
ucts and capacities" ( Y page

308).You can check the oil level in the engine:
R with the oil dipstick
Checking the oil level using the oil dip-
stick G
WARNING
Opening the hood when the engine is over-
heated or when there is a fire in the engine
compartment could expose you to hot gases
or other service products. There is a risk of
injury.
Let an overheated engine cool down before
opening the hood. If there is a fire in the
engine compartment, keep the hood closed
and contact the fire department. 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. Oil dipstick and engine oil filler neck
Only check the oil level when the engine is at
normal operating temperature. X Stop your vehicle as far away from traffic as
possible on level ground.
X Secure the vehicle to prevent it from rolling
away.
X Switch off the engine.
X Wait for five minutes.252
Engine compartment
Maintenance and care

X
Open the hood (Y page 251).
X Pull out oil dipstick :.
X Wipe oil dipstick : using a lint-free cloth.
X Insert oil dipstick : back into the guide
tube as far as it will go and remove it again.
If the level is between MIN mark = and
MAX mark ;, the oil level is adequate.
X If the oil level has dropped to or below mini-
mum mark =, open cap ? and add engine
oil

(Y page 253).
The difference in quantity between
marks ; and = is approximately
2 US quarts (2 liters).
X Close the hood.
Adding engine oil G
WARNING
Opening the hood when the engine is over-
heated or when there is a fire in the engine
compartment could expose you to hot gases
or other service products. There is a risk of
injury.
Let an overheated engine cool down before
opening the hood. If there is a fire in the
engine compartment, keep the hood closed
and contact the fire department. 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
If engine oil comes into contact with hot
components in the engine compartment, it
may ignite. There is a risk of fire and injury.
Make sure that engine oil is not spilled next
to the filler neck. Let the engine cool down
and thoroughly clean the engine oil off the
components before starting the engine. H
Environmental note
When adding oil, take care not to spill any. If
oil enters the soil or waterways, it is harmful
to the environment.
! Do not add too much oil. adding too much
engine oil can result in damage to the
engine or to the catalytic converter. Have
excess engine oil siphoned off.
! Do not use any additives in the engine oil.
This could damage the engine. Engine oil filler neck (example)
Observe the information regarding approved
motor oil under "Service products and capaci-
ties" (Y page

308).
i When releasing the hood, the key must be
inserted in the ignition lock and in position 0
– ignition off.
X Open the hood (Y page
251).
X Unscrew and remove cap :.
X Add engine oil.
X Replace cap : on the filler neck and
tighten.
When doing so, make sure that the cap
engages correctly.
X Check the oil level with the oil dipstick
(Y page

252).
X Close the hood. Coolant
G
WARNING
Service products may be poisonous and haz-
ardous to health. There is a risk of injury. Engine compartment
253
Maintenance and care
Z

Comply with instructions on the use, storage
and disposal of service products on the
labels of the respective original containers.
Always store service products sealed in their
original containers. Always keep service
products out of the reach of children. G
WARNING
Opening the hood when the engine is over-
heated or when there is a fire in the engine
compartment could expose you to hot gases
or other service products. There is a risk of
injury.
Let an overheated engine cool down before
opening the hood. If there is a fire in the
engine compartment, keep the hood closed
and contact the fire department. 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.
Coolant contains glycol and is therefore poi-
sonous. Also observe the safety notes under
"Service products and capacities"
(Y page
305). G
WARNING
The cooling system is pressurized, particu-
larly when the motor is warm. If you open
the cap, you could be scalded if hot coolant
sprays out. There is a risk of injury.
Let the engine cool down before you open
the cap. Wear protective gloves and protec-
tive eyewear when opening. Open the cap
slowly to release pressure.
Only check the coolant level and/or fill the
coolant if the vehicle is on a level surface and
the engine has cooled down. The coolant tem-
perature must be below

122 ‡ (50 †). The
coolant temperature gauge must no longer reach the first line after the letter
C on the
scale and/or the bar display.
! Check the engine cooling and heating sys-
tem regularly for leaks.
If a large quantity of coolant is lost, have the
cause traced and rectified at a qualified spe-
cialist workshop. G
WARNING
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.
! Take care not to spill any coolant on pain-
ted surfaces. You could otherwise damage
the paintwork. Example: cap and coolant expansion tank
Checking the coolant level
X Stop your vehicle as far away from traffic as
possible on level ground.
X Switch off the engine.
X Secure the vehicle to prevent it from rolling
away.
X Open the hood (Y page
251).
X Allow the engine to cool down.
X Unscrew cap : slowly about half a turn
counter-clockwise and allow excess pres-
sure to escape. 254
Engine compartment
Maintenance and care

X
Turn cap : further and remove it from cool-
ant expansion tank ;.
X Check the coolant level.
If the coolant is up to marker bar =
in the
filler neck when cold, there is a sufficient
amount of coolant in coolant expansion
tank ;.
If the coolant is approximately 0.59 in
(1.5 cm) above marker bar = in the filler
neck when warm, there is a sufficient
amount of coolant in coolant expansion
tank ;.
Adding coolant X If the coolant drops under marker bar = in
the filler neck, add coolant.
Observe the information on the correct cool-
ant mixture ratio and the required water
quality under "Service products and capaci-
ties" ( Y page

310). To prevent damage to
the engine cooling system, use only
approved corrosion inhibitor/antifreeze that
complies with the Mercedes-Benz Specifica-
tions for Service Products.
X Replace cap : and tighten in a clockwise
direction.
X Start the engine.
X Set the temperature in the vehicle interior to
the maximum output on the air-conditioning
system control panel.
X After approximately five minutes, switch off
the engine again and allow it to cool down.
X Check the coolant level again and add cool-
ant if necessary.
X Close the hood. Brake fluid
G
WARNING
Service products may be poisonous and haz-
ardous to health. There is a risk of injury.
Comply with instructions on the use, storage
and disposal of service products on the
labels of the respective original containers.
Always store service products sealed in their
original containers. Always keep service
products out of the reach of children. G
WARNING
Opening the hood when the engine is over-
heated or when there is a fire in the engine
compartment could expose you to hot gases
or other service products. There is a risk of
injury.
Let an overheated engine cool down before
opening the hood. If there is a fire in the
engine compartment, keep the hood closed
and contact the fire department. 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.
Brake fluid is hazardous to health. Also
observe the safety notes under "Service prod-
ucts and capacities"
(Y page 305). 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.
! If the brake fluid level in the brake fluid
reservoir has fallen to the MIN mark or
below, check the brake system immediately
for leaks. Also check the thickness of the
brake linings. Visit a qualified specialist
workshop immediately.
Do not add brake fluid. This does not cor-
rect the malfunction.
! Brake fluid corrodes paint, plastic and rub-
ber. If paint, plastic or rubber has come into
contact with brake fluid, rinse with water
immediately. Engine compartment
255
Maintenance and care Z

X
Thoroughly hose down the vehicle with a
gentle jet of water.
X Do not point the water jet directly towards
the air inlet grilles.
X Use plenty of water and rinse out the
sponge frequently.
X Rinse the vehicle with clean water and dry
thoroughly with a chamois.
X Do not let the cleaning agents dry on the
paintwork.
When using the vehicle in winter, remove all
traces of road salt deposits carefully and as
soon as possible.
Power washers G
WARNING
The water jet from a circular jet nozzle (dirt
blasters) can cause invisible exterior dam-
age to the tires or chassis components.
Components damaged in this way may fail
unexpectedly. There is a risk of an accident.
Do not use power washers with circular jet
nozzles to clean the vehicle. Have damaged
tires or chassis components replaced imme-
diately.
! Under no circumstances use power wash-
ers in the vehicle interior. The pressurized
water and associated spray produced by the
power washer could cause extensive dam-
age to the vehicle.
! When using high-pressure cleaning equip-
ment, maintain a minimum distance of
approx. 1 ft (30 cm
) between the spray noz-
zle and the vehicle parts. Do not use a
power washer with a round-jet nozzle. You
could damage the vehicle or engine parts.
! Keep the water jet moving constantly
while cleaning. This will avoid causing dam-
age to the vehicle.
Do not point the water jet at:
R door joints
R rear view camera
R air bellows
R brake hoses
R wheel balance weights
R electrical components
R electrical connections R
seals
R drive train, especially not at the inter-
mediate bearing of the propeller shaft
Cleaning the engine !
Water must not enter intake or ventilation
openings. When cleaning with high pressure
water or steam cleaners, the spray must not
be aimed directly at electrical components
or the terminals of electrical lines.
Preserve the engine after the engine has
been cleaned. Protect the belt drive system
from exposure to the preservative agent.
Also observe the information under "Power
washers"

(Y page 265).
Cleaning the paintwork !
Do not affix:
R stickers
R films
R magnetic plates or similar items
to painted surfaces. You could otherwise
damage the paintwork.
Scratches, corrosive deposits, areas affected
by corrosion and damage caused by inade-
quate care cannot always be completely
repaired. In such cases, visit a qualified spe-
cialist workshop.
X Remove impurities immediately, where pos-
sible, whilst avoiding rubbing too hard.
X Soak insect remains with insect remover
and rinse off the treated areas afterwards.
X Soak bird droppings with water and rinse off
the treated areas afterwards.
X Remove coolant, brake fluid, tree resin, oils,
fuels and greases by rubbing gently with a
cloth soaked in petroleum ether or lighter
fluid.
X Use tar remover to remove tar stains.
X Use silicone remover to remove wax.
Cleaning the windows G
WARNING
You could become trapped by the wind-
shield wipers if they start moving while
cleaning the windshield or wiper blades.
There is a risk of injury. Care
265
Maintenance and care
Z