engine MERCEDES-BENZ E-CLASS CABRIOLET 2018 Repair Manual

&
WARNING Risk of inju ryfrom touching
co mp onent parts under voltage
The ignition sy stem and the fuel injection
sy stem workunder high voltage. If youto uch
co mp onent parts which are under voltage,
yo u could recei vean electric shoc k.#
Neverto uch co mponents of the ignition
sy stem or the fuel injection sy stem
when the ignition is switched on. &
WARNING Risk of bu rns from hot com‐
ponent parts in the engine compartment
Cer tain components in the engine compart‐
ment can be very hot, e.g. the engine, the
ra diator and parts of theex haust sy stem. #
Allow the engine tocool down and only
to uch co mponent parts described in the
fo llowing. &
WARNING Risk of inju ryfrom using the
windscreen wipers while the engine bon‐
net is open
When the engine bonn etis open, and the
windscreen wipers are set in motion, you can
be trapped bythe wiper linkage. #
Alw ays switch off the windscreen wip‐
ers and ignition before opening the
engine bonn et. #
Toopen: pullthe le ver1 torelease the
bonn et. 394
Maintenance and care

#
Push the handle 1ofthe bonn etcatch
up wa rds and lift the bonn etby appr oximately
40 cm. #
Toclose: lowe rth e bonn etand let it fall from
a height of appr oximately 20 cm. #
Ifth e bonn etcan still be lif ted slightl y,open
th e bonn etagain and close it with a little
more forc e until it engages cor rectly. Engine oil
Che
cking the engine oil le vel using the oil
dip stick &
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: Re
quirements:
th e engine must ha vean oil dipstic k.If not, the
engine oil le vel can be checked only with the on-
board computer .
Depending on the engine, the oil dipstick may be
ins talled in the engine compartment in dif fere nt
locations. The
waiting time before checking the oil le vel
when the engine is at normal operating temp era‐
ture is five minutes. #
Park theve hicle on a le vel sur face. #
Pull oil dipstick 1out and wipe off. Maintenance and care
395

#
Slowly slide oil dipstick 1into the guide
tube tothestop, and pull it out again af ter
appr oximately thre e seconds.
R Oil le vel is cor rect: oil le vel is between 2
and 3.
R Oil le velto o low: oil le vel is at 3or
belo w.
R Oil le velto o high: oil le vel is abo ve2 . #
Ifth e oil le vel is too lo w,top up with 1 litre of
engine oil. #
Ifth e engine oil le vel is too high, ha vethe
exc ess engine oil remo ved immediately at a
qu alified specialist workshop.
Checking the engine oil le vel with an on-
board computer
Re quirements:
th e engine oil le vel is de term ined during driving.
De term ining the engine oil le vel can take up to
30 minutes with a normal driving style and even
longer with an active driving style.
In order torecei veare sult as quickly as possi‐
ble:
R warm upthe engine. R
park theve hicle on a le vel sur face.
R leav eth e engine running at idle speed.
On-board compu ter:
Service Engine oil level:
Yo u will see one of thefo llowing messa ges in
th e multifunction displa y: #
Engine oil level Measuring now: measu re‐
ment of the oil le vel is not yet possible.
Re peat there qu est af ter a maximum of 30
minutes' driving. #
Engine oil level OK andthe bar display for
indicating the oil le vel in the multifunction
display is green and is between "min" and
"max": the oil le vel is cor rect. #
Engine oil level Add 1.0 l andthe bar display
fo r indicating the oil le vel in the multifunction
display is orange and is below "min": top up
with 1 l of engine oil. #
Reduce engine oil level andthe bar display
fo r indicating the oil le vel in the multifunction
display is orange and is abo ve"max": drain off
theexc ess engine oil. Consult a qualified
specialist workshop. #
For engine oil level turn on ignition: switch on
the ignition tocheck the engine oil le vel. #
Engine oil level System inoperative : sensor
fa ulty or not inser ted. Consult a qualified
specialist workshop. #
Engine oil level System currently unavail. :
close the bonn et.
To pping up engine oil &
WARNING Risk of bu rns from hot com‐
ponent parts in the engine compartment
Cer tain components in the engine compart‐
ment can be very hot, e.g. the engine, the
ra diator and parts of theex haust sy stem. #
Allow the engine tocool down and only
to uch co mponent parts described in the
fo llowing. 396
Maintenance and care

&
WARNING Risk offire and injury from
engine oil
If engine oil comes into con tact wi thhot
component parts in the engine compart‐
ment, it may ignite. #
Make sure that no engine oil is spilled
next tothefiller opening. #
Allow the engine tocool off and thor‐
oughly clean the engine oil from compo‐
nent parts before starting theve hicle. *
NO
TEEngine dama gecaused byan
incor rect oil filter, incor rect oil or addi‐
tives #
Do not use engine oils or oil filters
which do not cor respond tothe specifi‐
cations explicitly prescribed forthe
service inter vals. #
Do not alter the engine oil or oil filter in
order toachie velonger change inter vals
th an presc ribed. #
Do not use additives. #
Follow the instructions in the service
inter val display rega rding the oil
ch ange. *
NO
TEDama gecaused bytopping up too
much engine oil To
o much engine oil can damage the engine
or the catalytic con verter. #
Have excess engine oil remo ved at a
qu alified specialist workshop. #
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 395). Maintenance and care
397

Checking
the coolant le vel &
WARNING Risk of bu rns from hot com‐
ponent parts in the engine compartment
Cer tain components in the engine compart‐
ment can be very hot, e.g. the engine, the
ra diator and parts of theex haust sy stem. #
Allow the engine tocool down and only
to uch co mponent parts described in the
fo llowing. &
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. #
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 467) 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. 398
Maintenance and care

#
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. #
Remo vecap 1bytheta b. #
Top up thewa sher fluid. Ke
eping the air-water duct free #
Keep the area between the bonn etand the
windscreen free of deposits, e.g. ice, sn ow
and lea ves. Cleaning and care
Information on
washing theve hicle in a car
wa sh &
WARNING Risk of an accident due to
re duced braking po wer af terwa shing the
ve hicle
Braking ef ficiency is reduced af terwa shing
th eve hicle. #
Afterth eve hicle has been washed,
brake carefully while paying attention to
th e traf fic conditions until braking
po we r has been fully restored. Maintenance and care
399

specialist wo
rkshop or toa collection
point for used batteries. If
yo u ha vetodisconnect the12 V batter y,con‐
ta ct a qualified specialist workshop.
Comply with saf ety no tes and take protective
measures when handling batteries. Risk of
explosion. Fire, naked
flames and smoking are
prohibi ted when handling the batter y.
Av oid creating spar ks. Electrolyte
or battery acid is cor ro‐
sive. Avoid contact with the skin, eyes
or clo thing. Wear suitable pr otective
clo thing, in particular glove s, an
apron and a face mas k.Immedia tely
ri nse electrolyte or acid splashes off
with clean water.Consult a doc tor if
necessar y. We
ar saf etygl asses. Ke
ep children away. Obser
vethis Owner's Manual.
Obser vethefo llowing if you do not intend touse
th eve hicle over an extended pe riod of time:
R Activate standby mode.
R Alternatively: connect the battery toa bat‐
te ry charge r appro vedby Mercedes-Benz or
consult a qualified specialist workshop to
disconnect the batter y. Note
s onstarting assi stance and on charg‐
ing the12 V battery Ve
hicles with a lithium-ion battery
When charging the battery and during starting
assis tance, al ways use the jump-s tart connec‐
tion point in the engine compartment.
* NO
TEDama getothe battery from over‐
vo ltage When
charging using a bat tery charge r with‐
out a maximum charging voltage, the battery
or the on-board electronics may be damaged. #
Only use battery charge rs with a maxi‐
mum charging voltage of 14.4 V. All
other vehicles
When charging the battery and during starting
assis tance, al ways use the jump-s tart connec‐
tion point in the engine compartment. 422
Breakdown assis tance

*
NO
TEDamaging the battery thro ugh
ove rvoltage When using a battery
charge r without a maxi‐
mum charging voltage, the battery or the
ve hicle electronics may be damaged. #
Only use battery charge rs with a maxi‐
mum charging voltage of 14.8 V. &
WARNING Risk ofexplosion from hydro‐
ge nga s igniting
A battery generates hydrogen gas during the
ch arging process. If there is a short circuit or
spar ksstart toform ,th ere is a danger of the
hy drogen gas igniting. #
Make sure that the positive term inal of
th e connected battery does not come
into conta ct withvehicle parts. #
Never place me tal objects or tools on a
batter y. #
When connecting and disconnecting the
batter y,yo u must obse rveth e descri‐
bed order forth e battery clamps. #
When giving starting assis tance, al ways
make sure that you on lyconnect bat‐
te ry term inals with identical polarity. #
During starting assis tance, you must
obse rveth e described order for con‐
necting and disconnecting the jump
lead. #
Do not connect or disconnect the bat‐
te ry cla mp s while the engine is running. &
WARNING Risk ofexplosion during
ch arging process and starting assis tance
During thech arging process and starting
assis tance, the battery may release an explo‐
sive gas mixture. #
Avoid fire , naked flames, creating
spar ksand smoking. #
Make sure that there is suf ficient venti‐
lation du ring thech arging process and
during starting assis tance. #
Do not lean over a batter y. &
WARNING Risk ofexplosion from a fro‐
zen battery
A dischar ged battery may freeze at temp era‐
tures slightly abo veor below freezing point.
During starting assis tance or battery charg‐
ing, bat tery gas may be released. #
Alw aysth aw a frozen bat tery out first
before charging it or per form ing start‐
ing assis tance. If
th e indicator/warning lamps in the instrument
clus ter do not light up at low temp eratures, it is
ve ry likely that the dischar ged battery has fro‐
zen. In this case you may neither jump-s tart the
ve hicle nor charge the batter y.
The service life of a battery that has been
th awe d may be dramatically shor tened. The
st arting characteristics may be impaired, espe‐
cially at low temp eratures.
It is recommended that you ha veathaw ed bat‐
te ry checked at a qualified specialist workshop. Breakdown assis
tance 423

All
vehicles
* NO
TEDama gecaused bynumerous or
ex tended attem ptsto start the engine Nume
rous or extended attem ptsto start the
engine may damage the catalytic con verter
due tonon-combu sted fuel. #
Avoid numerous and extended attem pts
to start the engine. Obser
vethefo llowing points during starting
assis tance and when charging the battery:
R Only use undamaged jump lead/charging
cables with a suf ficient cross-section and
insula tedte rm inal clamps.
R Non- insulated parts of thete rm inal clamps
must not come into con tact wi thother me tal
parts while the jump lead/charging cable is
connected tothe battery/jump-s tart connec‐
tion point.
R The jump lead/charging cable must not
come into contact wi thany parts which may
mo vewhen the engine is running. R
Alw ays make sure that nei ther you nor the
battery is elect rostatically charge d.
R Keep away from fire and naked flames.
R Do not lean overth e batter y.
Obser vethe additional following points when
ch arging the battery:
R Only use battery charge rs tested and
appr oved for Mercedes-Benz.
R Read the battery charge r's operating instruc‐
tions before charging the batter y.
Obser vethe additional following points during
st arting assis tance:
R Starting assis tance may only be pr ovided
using batteries with a nominal voltage of
12 V.
R The vehicles must not touch.
R Petrol engine: only acceptstarting assis‐
ta nce if the engine and exhaust sy stem are
cold. St
arting assi stance and charging the12 V
battery Re
quirements:
R The vehicle is secured with the electric park‐
ing brake.
R Vehicles with automatic transmission: the
transmission is in position j.
R The ignition and all electrical consumers are
switched off.
R The bonnet is open. 424
Breakdown assi stance

#
Slide co ver1 of positive clamp 2onthe
jump-s tarting connection point in the direc‐
tion of the ar row. #
Connect positive clamp 2onyour vehicle to
th e positive pole of the donor battery using
th e jump lead/charging cable. Alw ays begin
with positive clamp 2onyour ow nve hicle
fi rs t. #
During starting assi stance: start the
engine of the donor vehicle and run at idle
speed. #
Connect the negative pole of the donor bat‐
te ry and ear thpoint 3ofyour ow nve hicle
by using the jump lead/charging cable. Begin
with the donor battery firs t. #
During starting assi stance: start the
engine of your ow nve hicle. #
During thech arging process: start the
ch arging process. #
During starting assi stance: letthe engines
ru nfo r se veral minutes. #
During starting assi stance: before discon‐
necting the jump lead, switch on an electrical
consumer in your ow nve hicle, e.g. there ar
wind owheater or lighting.
When thest arting assis tance/charging process
is compl ete, per form thefo llowing steps: #
First,re mo vethe jump lead/charging cable
from ear thpoint 3and the negative pole of
th e donor batter y,then from positive clamp
2 and the positive pole of the donor bat‐ te
ry. Begin ea chtime wi th the conta cts on
yo ur ow nve hicle firs t. #
Afterre moving the jump lead/charging
cable, close co ver1 of positive clamp 2.
Fu rther information can be obtained at a quali‐
fi ed specialist workshop. Re
placing the 12V battery #
Obser vethe no tes on the12 V battery
(→ page 420).
Mercedes-Benz recommends that you ha vethe
12 V battery replaced at a qualified specialist
wo rkshop, e.g. at a Mercedes-Benz Service
Centre.
Obser vethefo llowing no tes if youwa ntto
re place the battery yourself:
R Alw aysre place a faulty bat tery with a battery
which meets the specific vehicle require‐
ments.
The vehicle is equipped with an AGMtech nol‐
ogy battery (Absorbent Glass Mat) or a li th‐
ium-ion batter y.Fu llve hicle functionality is Breakdown assis
tance 425