engine overheat MERCEDES-BENZ CLS COUPE 2018 Owners Manual

#
Do not shi ftdown on slippery road sur‐
fa ces toinc rease the engine braking
ef fect. &
DANG ER Risk of fata l injuries due topoi‐
sonous exhaust gases
If th eta ilpipe is bloc ked or suf ficient ventila‐
tion is not possible, poisonous exhaust gases
such as carbon monoxide may enter theve hi‐
cle. This is the case, forex ample, if theve hi‐
cle is stuck in sn ow. #
When the engine or thest ationary
heater are running, keep theta ilpipe
and the area around theve hicle clear of
sno w. #
Open a window on the side of theve hi‐
cle facing the wind toensure an ade‐
qu ate supply of fresh air. &
WARNING Risk of accident due tothe
brake sy stem overheating
If yo u lea veyour foot on the brake pedal
when driving, the brake sy stem may over‐
heat.
This increases the braking dis tance and the
brake sy stem may evenfa il. #
Never use the brake pedal as a foot re st. #
Do not depress the brake pedal and the
accelerator pedal at the same time
while driving. *
NO
TECausing wearto the brake linings
by permanently depressing the brake
pedal #
Do not permanently depress the brake
pedal while driving. #
Touse braking ef fect of the engine,
shift toa lo werge ar in good time. *
NO
TEDama getothe driv etra in and
engine when pulling away #
Do not warm upthe engine when sta‐
tionar y.Pull away immediatel y. #
Avoid high engine speeds and full thro t‐
tle until the engine has reached its
operating temp erature. #
Do not allow the wheels tospin. *
NO
TEDama getothe catalytic con verter
due tonon-combu sted fuel The engine is not
running smo othly and is
misfiring.
Non-combus ted fuel may get into the cata‐
lytic con verter. #
Only depress the accelera tor pedal
slightl y. #
Have the cause rectified immediately at
a qu alified specialist workshop. Driving and parking
15 5

#
Do not get into theve hicle again during
th ere fuelling process.
Otherwise, electros tatic charge could
build up again. &
WARNING Risk offire from fuel mixture
Ve hicles with a diesel engine:
If yo u mix diesel fuel with petrol, theflash
point of the fuel mixture is lo werth an that of
pure diesel fuel.
While the engine is running, component
pa rts in theex haust sy stem may overheat
without warning. #
Neverre fuel using petrol. #
Never mix petrol with diesel fuel. *
NO
TEDama gecaused bythe wrong fuel Ve
hicles with a petrol engine:
Even small amounts of the wrong fuel could
re sult in damage tothe fuel sy stem, the
engine and the emission control sy stem. #
Only refuel using unleaded, sulphu r-free
fuel that con form sto European EN 228,
or an equi valent specification. #
The RONrequ irement is located in the
fuel filler flap.
Fu el of this specification may con tain up to
10 %ethanol. Your vehicle is suitable for use
with E10 fuel.
Ne verre fuel using:
R diesel
R regular petrol with an octane number
lo we rth an 91 RON
R petrol with more than 10%ethanol byvol‐
ume, e.g. E15, E20, E85, E100
R petrol with more than 3% me thanol by
vo lume, e.g. M15, M30
R petrol with additives con taining me tal
If yo u acciden tally refuel with the wrong fuel: #
Do not switch the ignition on. #
Consult a qualified specialist workshop. *
NO
TEDama gecaused bythe wrong fuel Ve
hicles with a diesel engine:
Even small amounts of the wrong fuel could
re sult in damage tothe fuel sy stem, the
engine and the emission control sy stem. #
Only refuel using sulphu r-free diesel
fuel that con form sto European stand‐
ard EN 590, or an equivalent specifica‐
tion.
In countries without sulphur-f ree diesel
fuel, only refuel with lo w-sulphur diesel
fuel with a sulphur content less than
50 ppm. #
Vehicles without diesel particulate
fi lter: refuel using only diesel fuel with
a sulphur content less than 500 ppm.
Ne verre fuel using:
R petrol
R marine diesel
R heating oil
R pure bio-diesel fuel or vege table oil Driving and parking
167

1
Cruise cont rol is selec ted
2 Speed is sa ved, cruise control is deactivated
3 Speed is sa ved, cruise control is activated
% The segments extending from the cur rent
st ored speed tothe end of the scale, or to
th e set winter tyre limit, light up in the
speedome ter.
Sy stem limitations
Cruise control may be unable tomaintain the
st ored speed on uphill gradients. The stored
speed is resumed when the gradient evens out.
Change into a lo werge ar in good time on long
and steep downhill gradients. Take particular no
te ofthis when driving a laden vehicle. By
doing so, you will make use of the engine's brak‐
ing ef fect. This relie vesth e load on the brake
sy stem and pr events the brakes from overheat‐
ing and wearing tooqu ickl y.
Do not use cruise control in thefo llowing situa‐
tions:
R In traf fic situations whi chrequ ire frequent
ch anges of speed, e.g. in heavy traf fic, on
winding roads.
R On slippe ryroads. Accelerating can cause
th e drive wheels tolose traction and the
ve hicle could then skid.
R Ifyo u are driving when visibility is poor.
Fu nction of the limi ter
The limiter restricts the speed of theve hicle. To
re duce the speed tothe set speed, the limiter
applies the brakes automaticall y.
Yo u can limit the speed as follo ws:
R Variable: for speed limits, e.g. in built-up
areas.
R Perm anen t:for long-term speed restrictions,
e.g. when driving in winter tyre mode. The
variable limiter is operated using the cor re‐
sponding steering wheel buttons. You can store
any road speed abo ve20 km/h up tothe maxi‐
mum road speed or tothe set winter tyre limit.
Yo u can also per form settings while theve hicle
is stationary if theve hicle has been star ted.
If yo ufa ilto adapt your driving style, the limiter
can neither reduce therisk of an accident nor
ov erride the la wsof ph ysics. It cannot take into
account road, weather or traf fic conditions. The
limiter is only an aid. You are responsible for
maintaining a safe dis tance totheve hicle in
front, forve hicle speed, for braking in good time
and forst ay ing in lane.
Displa ysinthe Instrument Display
The status of the limiter and thestored speed
are shown in the multifunction displa y. Driving and pa
rking 19 3

R
Speed limiter (→ page 193)
R Active Dis tance Assi stDISTRONIC
(→ page 196)
* NO
TEEngine dama gedue toexcessively
high engine speeds The engine will be damaged if
you drive with
th e engine in theov errevving range. #
Do not drive wi th the engine in theove r‐
re vving range. The fuel supply is inter
rupted toprotect the
engine when there d mark on there v counter 3
(o ve rrev ving range) is reached.
During no rmal operating conditions, coolant
te mp erature display 4may rise to120 °C. &
WARNING Danger of bu rns when open‐
ing the bonn et
If yo u open the engine bonn etwhen the
engine has overheated or during a fire inthe
engine compartment, you could come into
contact with hot gases or other escaping
operating fluids. #
Before opening the bonn et, allow the
engine tocool down. #
Intheeve nt of a fire inthe engine com‐
partment, keep the engine bonn et
closed and call thefire service. Ve
hicles with a 48 V on-board electrical sys‐
te m (EQ Boo sttech nology) R
POWER 1shows th e electrical drive sup‐
port as a percentage.
R CHARGE 2showsthe electric mo tor's recu‐
peration po wer as a percentage. õ
showsthe drive sy stem's operational read‐
iness . Overview of
the but tons on thest eering
wheel 1
¤ Back/Home button (press and hold),
on-board computer
2 Touch Control, on-board co mputer
3 Control panel for cruise control/limiter or
Ac tive Dis tance Assi stDISTRONIC
4 Control panel for multimedia sy stem:
£ LINGU ATRO NIC or voice control sys‐
tem 254
Instrument Display and on-board computer

#
With your hand flat, push down active bonnet
1 inthe area around the hinges on bo th
sides (ar rows).
In doing so, the actuator is depressurised
and you may hear a hissing sound.
The engine bonnet must en gage in position. #
Ifth e active bonn etcan be raised slight lyat
th ere ar in the area of the hinges, repeat the
st ep until it engages cor rectl y. Opening/closing
the bonnet &
WARNING Risk of accident due todriv‐
ing with the engine bonn etunlo cked
An unloc ked engine bonn etmay open up
when theve hicle is in motion and block your
vie w. #
Never unlock the engine bonn etwhen
driving. #
Before every trip, ensure that the
engine bonn etis loc ked. &
WARNING Risk of accident and inju ry
when opening and closing the engine
bonn et
When opening or closing the engine bonn et,
it may suddenly drop into the end position.
There is a risk of injury for an yone in the
engine bonn et's range of mo vement. #
Only open or close the engine bonn et
when there are no persons in the
engine bonn et's range of mo vement. &
WARNING Danger of bu rns when open‐
ing the bonn et
If yo u open the engine bonn etwhen the
engine has overheated or during a fire inthe
engine compartment, you could come into
contact with hot gases or other escaping
operating fluids. #
Before opening the bonn et, allow the
engine tocool down. #
Intheeve nt of a fire inthe engine com‐
partment, keep the engine bonn et
closed and call thefire service. &
WARNING Risk of inju rydue tomoving
parts
Cer tain components in the engine compart‐
ment may continue tomo veor suddenly
mo veagain even af terth e ignition has been
switched off, e.g. the cooler fan.
Ma kesure of thefo llowing before per form ing
ta sks in the engine compartmen t: #
Switch the ignition off. Maintenance and care
389

#
Turn cap 1anti-clockwise and remo veit. #
Top up the engine oil. #
Replace cap 1and turn it clockwise as far
as it will go. #
Check the oil le vel again (→ page 391). Checking
the coolant le vel &
WARNING Danger of bu rns from hot
component parts in the engine compart‐
ment
Cer tain component parts in the engine com‐
partment may be very hot, e.g. the engine,
th era diator and parts of theex haust sy stem. #
Let the engine cool down and only
to uch the component parts described
below: &
WARNING Danger of bu rns when open‐
ing the bonn et
If yo u open the engine bonn etwhen the
engine has overheated or during a fire inthe
engine compartment, you could come into
contact with hot gases or other escaping
operating fluids. #
Before opening the bonn et, allow the
engine tocool down. #
Intheeve nt of a fire inthe engine com‐
partment, keep the engine bonn et
closed and call thefire service. &
WARNING Risk of scalding from hot
coolant
The engine cooling sy stem is pressurised,
particularly when the engine is warm. If you
open the cap, you could be scalded byhot
coolant spr aying out. #
Let the engine cool down before open‐
ing the cap. #
When opening the cap, wear pr otective
gl ove s and saf etygl asses. #
Open the cap slowly torelease pres‐
sure. #
Park theve hicle on a le vel sur face. Maintenance and care
393

#
Check the coolant temp erature display in the
instrument clus ter.
The coolant temp erature must be below
70 °C. #
Slowly turn cap 1anti-clockwise torelie ve
ov erpressure. #
Continue turning cap 1anti-clockwise and
re mo veit.
The coolant le vel is cor rect:
R ifth e engine is cold, up tomar ker bar 2
R ifth e engine is warm, up to1.5 cm over
mar ker bar 2 #
If necessar y,top up with coolant that has
been appr ovedby Mercedes-Benz.
R Further information on coolant
(→ page 459). To
pping up the windsc reen washer sy stem &
WARNING Danger of bu rns from hot
component parts in the engine compart‐
ment
Cer tain component parts in the engine com‐
partment may be very hot, e.g. the engine,
th era diator and parts of theex haust sy stem. #
Let the engine cool down and only
to uch the component parts described
below: &
WARNING Danger of bu rns when open‐
ing the bonn et
If yo u open the engine bonn etwhen the
engine has overheated or during a fire inthe
engine compartment, you could come into
contact with hot gases or other escaping
operating fluids. #
Before opening the bonn et, allow the
engine tocool down. #
Intheeve nt of a fire inthe engine com‐
partment, keep the engine bonn et
closed and call thefire service. &
WARNING ‑ Risk of fire and injury due to
windscreen washer concentrate
Wi ndsc reen washer concentrate is highly
fl ammable. It could ignite if it comes into
con tact wi thhot engine component parts or
th eex haust sy stem. #
Make sure that no windsc reen washer
concentrate spills out next tothefiller
opening. 394
Maintenance and care

CLS 350, CLS 350 4MATIC:
onlyrefuel using
super unleaded petrol with at lea st98 RON,if
yo u wish toachie vemaximum engine output.
Alternatively, you can also refuel using unleaded
petrol with at lea st95 RON.
All models: as atemp orary measure, if there c‐
ommended fuel is not available, you may also
use regular unleaded petrol with an octane num‐
ber of at least 91RON. This may reduce engine
output and increase fuel consum ption.
Ne verre fuel using petrol with an even lo wer
RO N.
Fu rther information on fuel can be obtained at a
fi lling station or a qualified specialist workshop.
Information on additives in petrol
Obser vethe no tes on operating fluids
(→ page 452).
* NO
TEDama gefrom use of unsuitable
additives Even small amounts of
the wrong additive
may lead tomalfunctions occur ring. #
Only add cleaning additives recommen‐
ded byMercedes-Benz tothe fuel. Mercedes-Benz
recommends that you use fuel
brands that ha veadditives.
In some countries, the fuel available may not
ha ve suf ficient additives. Residue could build up
in the fuel injection sy stem as a result. In this
case, in consultation with a Mercedes-Benz
service centre, the fuel may be mixed with the
cleaning additive recommended byMercedes-
Benz. Be sure toobser vethe no tes and mixing
ra tios speci fied on the conta iner.
Information on fuel grades forve hicles with
a diesel engine
Gene ral no tes
Obser vethe no tes on operating fluids
(→ page 452). &
WARNING Risk offire from fuel mixture
If yo u mix diesel fuel with petrol, theflash
point of the fuel mixture is lo werth an that of
pure diesel fuel. While
the engine is running, component
pa rts in theex haust sy stem may overheat
without warning. #
Neverre fuel using petrol in diesel
engines. #
Never mix petrol with diesel fuel. *
NO
TEDama gecaused bythe wrong fuel Even small amounts of
the wrong fuel could
re sult in damage tothe fuel sy stem, the
engine and the emission control sy stem. #
Only refuel using sulphu r-free diesel
fuel that con form sto European stand‐
ard EN 590, or an equivalent specifica‐
tion.
In countries without sulphur-f ree diesel
fuel, refuel using only lo w-sulphur diesel
fuel with a sulphur content less than
50 ppm. #
Vehicles without diesel particulate
fi lter: refuel using only diesel fuel with
a sulphur content less than 500 ppm. Te
ch nical da ta455

#
Allow the engine tocool down before
yo uto p up the antif reeze. #
Make sure that no antifreeze spills out
next tothefiller opening. #
Thoroughly clean the antif reeze from
component parts before starting the
ve hicle. *
NO
TEDama gecaused byincor rect cool‐
ant #
Only add coolant that has been pre‐
mixed with therequ ired antifreeze pro‐
te ction.
Information on coolant is available at thefo l‐
lowing locations:
R inthe Mercedes-Benz Specification for
Operating Fluids 310.1
- at http://be vo.mercedes-benz.com
- inthe Mercedes-Benz BeVo app
R at a qualified specialist workshop *
NO
TEOverheating at high outside tem‐
peratures If an inapp
ropriate coolant is used, the
engine cooling sy stem is not suf ficiently pro‐
te cted against overheating and cor rosion at
high outside temp eratures. #
Alw ays use coolant appr ovedby
Mercedes-Benz. #
Obser vethe instructions in the
Mercedes-Benz Specifications for Oper‐
ating Fluids 310.1. Ha
ve the coolant regularly replaced at a qualified
specialist workshop.
The proportion of cor rosion inhibitor/antifreeze
concentrate in the engine cooling sy stem should
be:
R a minimum of 50% (antifreeze pr otection
down toappr oximately -37 °C)
R a maximum of 55% (antifreeze pr otection
down to-45 °C) Note
s on windscreen washer fluid Obser
vethe no tes on operating fluids
(→ page 452). &
WARNING ‑ Risk of fire and injury due to
windscreen washer concentrate
Wi ndsc reen washer concentrate is highly
fl ammable. It could ignite if it comes into
con tact wi thhot engine component parts or
th eex haust sy stem. #
Make sure that no windsc reen washer
concentrate spills out next tothefiller
opening. *
NO
TEDama getotheex terior lighting
due tounsuitable windsc reen washer
fl uid Uns
uitable windsc reen washer fluids may
damage the plastic sur face of theex terior
lighting. #
Only use windscreen washer fluids
which are also suitable for use on plas‐ 460
Tech nical da ta

Engine
Display messages
Possible causes/consequences and M
MSolutions
Top up coolant See Own-
er’s Manual *T
he coolant le vel is too lo w.
* NO
TEEngine dama gedue toinsuf ficient coolant #
Avoid long journe yswith insuf ficient coolant. #
Add coolant (→ page 393).
?
Coolant Stop vehicle
Switch engine off *T
he coolant is too hot. #
Stop theve hicle immediately, paying attention toroad and traf fic conditions, and switch off the engine. &
WARNING Danger of bu rns when opening the bonn et
If yo u open the engine bonn etwhen the engine has overheated or during a fire inthe engine compartment, you
could come into contact wi thhot gases or other escaping operating fluids. #
Before opening the bonn et, allow the engine tocool down. #
Intheeve nt of a fire inthe engine compartment, keep the engine bonn etclosed and call thefire service. #
Wait until the engine has cooled down. #
Make sure that the air supply tothera diator is not obstructed. #
Avoiding significant loads on the engine, drive tothe nearest qualified specialist workshop. In doing so, ensure
th at the coolant temp erature display remains below 120 °C. Displ
aymessa ges and warning/indicator lamps 493