engine MERCEDES-BENZ E-CLASS CABRIOLET 2021 Service Manual

On-board computer:
4 Service 5
Engine oil level
One of thefo llowing message s will appear onthe
inst rument displa y:
R Engine oil level Measuring now: measu rement
of the oil le vel is not yet possible. #
Repeat there qu est aTer a maximum of
30 minutes' driving.
R Engine oil level OK andthe bar display for
indicating the oil le vel on the inst rument dis-
play is green and is between "min" and "max":
th e oil le vel is cor rect.
R Engine oil level Add 1,0 l andthe bar display
fo r indicating the oil le vel on the inst rument
display is orange and is below "min": #
Add 1 l of engine oil.
R Reduce engine oil level andthe bar display for
indicating the oil le vel on the inst rument dis-
play is orange and is abo ve"max": #
Drain o. any excess engine oil that has been
added. Todo so, consult a quali/ed specialist
wo rkshop.
R For engine oil level turn on ignition #
Switch on theve hicle tocheck the engine oil
le ve l.
R Engine oil level System inoperative: The oil
le ve l sensor is defective or not connected. #
Consult a quali/ed specialist workshop.
R Engine oil level System currently unavail. #
Close the bonnet.
T
T opping up engine oil
opping up engine oil &
W
WARNING
ARNING Risk of burns from hot compo-
nent parts in the engine compartment
Cer tain component parts in the engine com-
partment can be very hot, e.g. the engine, the
cooler and parts of theex haust system. #
Allow the engine tocool down and only
to uch component parts described in the
fo llowing. &
W
WARNING
ARNING Risk of /re and injury from
engine oil
If engine oil comes into contact with hot com-
ponent parts in the engine compartment, it
may ignite. #
Make sure that no engine oil is spilled
next tothe /ller opening. #
Allow the engine tocool o. and thor-
oughly clean the engine oil from compo-
nent parts before starting theve hicle. *
N
NOOTE
TE Engine damage caused byan inco r-
re ct oil /lter, incor rect oil or additi ves #
Do not use engine oils or oil /lters which
do not cor respond tothe speci/cations
ex plicitly prescribed forth e service inter-
va ls. #
Follow the inst ructions on the service
inter val display forch anging the engine
oil and obser vethe prescribed change
inter vals. #
Do not use additives. 302 302
Maintenance and care

*
N
N O
OTE
TE Damage caused bytopping up too
much engine oil To
o much engine oil can damage the engine or
th e catalytic con verter. #
Have excess engine oil remo ved at a
qu ali/ed specialist workshop. %
Depending on driving st yle, theve hicle con-
sumes up to0.8 litre of oil per 1000 km. The
oil consum ption may be higher than this when
th eve hicle is new or if you frequently drive at
high engine speeds. #
Turn cap 1anti-clockwise and remo veit. #
Top up the engine oil. #
Replace cap 1and turn it clockwise until it
engages. #
Check the oil le vel again (/ page 301). Chec
Chec
king t
king t he coolant lev
he coolant lev el
el &
W
WARNING
ARNING Risk of burns from hot compo-
nent parts in the engine compartment
Cer tain component parts in the engine com-
partment can be very hot, e.g. the engine, the
cooler and parts of theex haust system. #
Allow the engine tocool down and only
to uch component parts described in the
fo llowing. &
W
WARNING
ARNING Risk of scalding from hot cool-
ant
If yo u open the cap, you could be scalded. #
Let the mo tor cool down before opening
th e cap. #
When opening the cap, wear pr otective
glo ves and saf ety glasses. #
Open the cap slo wlytorelease pressure. Maintenance and care
303
303

#
Park theve hicle on a le vel sur face. #
Check the coolant temp erature display in the
inst rument clus ter.
The coolant temp erature must be below 70°C. #
Slowly turn cap 1anti-clockwise torelease
ove rpressure. #
Continue turning cap 1anti-clockwise and
re mo veit. The coolant le
vel is cor rect in thefo llowing cases:
R Ifth e engine is cold, the coolant is up to
mar ker bar 2.
R Ifth e engine is warm,th e coolant is up to
1.5 cm overth e mar ker bar 2. #
If necessar y,top up with coolant that has
been appr ovedfo r Mercedes-Benz.
% Further information on coolant (/ page 365) T
T
opping up t
opping up t he windscr
he windscreen w
een washer syst
asher syst em
em &
W
WARNING
ARNING Risk of burns from hot compo-
nent parts in the engine compartment
Cer tain component parts in the engine com-
partment can be very hot, e.g. the engine, the
cooler and parts of theex haust system. #
Allow the engine tocool down and only
to uch component parts described in the
fo llowing. &
W
WARNING
ARNING ‑ Risk of /re and injury due to
windscreen washer concent rate
Wi ndsc reen washer concent rate is highly 0am-
mable. It could ignite if it comes into contact
with hot engine component parts or the
ex haust system. #
Make sure that no windscreen washer
concent rate spills out next tothe /ller
opening. 304 304
Maintenance and care

Maintain a distance of at least 70 cm between
th efo il-co vered parts of theve hicle and the
nozzle of the high-pressure cleaner. Mo vethe
high-pressure cleaner nozzle around whilst
cleaning. The waterte mp erature of the high-
pressure cleaner must not exceed 60°C.
R Obser vethe information on the cor rect dis-
ta nce in the equipment manufacturer's oper-
ating inst ructions.
R Do not direct the nozzle of the high-pressure
cleaner directly at sensitive parts, such as
tyres, soT top, wind de0ector net, gaps, elec-
trical components, batteries, light sources and
ve ntilation slits. W W
ashing t
ashing t he v
he vehicle b
ehicle b y hand
y hand *
N NOOTE TE Engine damage due towa ter ing ress #
Take care not topoint thewa ter jet
directly towa rdsth e air inlet grille below
th e bonnet. obser
vethe legal requ irements, e.g. in a number
of countries, washing byhand is only permitted in
special lydesignated wash ba ys. #
Use a mild cleaning agent, e.g. car shampoo. #
Washtheve hicle with luk ewarm water using a
soT car sponge. When doing so, do not
ex pose theve hicle todirect sunlight. #
Carefully hose theve hicle o. with water and
dry using a chamois.
% Obser vethe no tes on the care of car parts
(/ page 311). N No
ot
tes on paintw
es on paintw or
ork/matt
k/matt /nish
/nishpaintw
paintw or
ork care
k care To
avo id damaging the paintwork and inter fering
with the driving assistance systems, please
obser vethefo llowing no tes:
P
P aint
aint
R Insect remains: soak with insect remo ver and
ri nse o. the treated areas aTer wards.
R Bird droppings: soak with water and rinse o.
aTer wards. R
Tree resin, oils, fuels and greases: remo veby
ru bbing gently with a clo thsoaked in petro-
leum ether or lighter 0uid.
R Coolant and brake 0uid: remo vewith a damp
clo thand clean water.
R Tar stains: use tarre mo ver.
R Wax: use silicone remo ver.
R Do not attach sti ckers, /lms or similar materi-
als. Only ha ve/lm attached tothe bumper at
a quali/ed specialist workshop.
R Remo vedirt immediatel y,where possible.
Matt Matt /nish /nish
R Only use care products appr ovedfor
Mercedes-Benz.
R Do not attach stic kers, /lms or similar materi-
als. Only ha ve/lm attached tothe bumper at
a qu ali/ed specialist workshop.
R Do not polish theve hicle and light-alloy
wheels.
R Only use car washes that cor respond tothe
latest engineering standards. Maintenance and care
307
307

If
yo u ha vetodisconnect the 12 V batter y,con-
ta ct a quali/ed specialist workshop.
Comply with saf ety no tes and take protective
measures when handling batteries. Risk of
explosion. Fire
, naked 0ames and smoking are
prohibi ted when handling the batter y.
Av oid creating spar ks. Electrolyte or battery acid is cor
rosive.
Av oid contact with the skin, eyes or
clo thing. Wear suitable pr otective
clo thing, in particular glo ves, an apron
and a face mask. Immediately rinse
electrolyte or acid splashes o. with
clean water. Consult a doctor if neces-
sar y. We
ar saf ety glasses. Ke
ep children away. Obser
vethis Owner's Manual.
Obser vethefo llowing if you do not intend touse
th eve hicle over an extended period of time:
R Activate standby mode.
R Alternativel y:connect the battery toa battery
ch arge r appr ovedby Mercedes-Benz or con-
sult a quali/ed specialist workshop todiscon-
nect the batter y. N N
o
ot
tes on st
es on st ar
arting assist
ting assist ance and c
ance and c har
harging t
ging t he 12
he 12
V batt
V batt ery
ery All v All v
ehicles
ehicles
When charging the battery and during starting
assistance, alw ays use the jump-start connection
point in the engine compartment. *
N
NOOTE
TE Damage tothe battery from over-
vo ltage When
charging using a battery charge r without
a re striction of the maximum charging voltage,
th e battery or the on-board electronics can be
damaged. #
Only use battery charge rs with a maxi-
mum charging voltage of 14.8 V. &
W
WARNI NG
ARNI NGRisk of explosion due tohydro-
ge nga s igniting
If, when charging a batter y,there is a short
circuit or spar ksstart toform ,th ere is a dan-
ge r of hydrogen gas igniting. #
Take care that the positive clamp con-
nected toa battery does not come into
contact with vehicle parts. #
Never place me tal objects or tools on a
batter y. #
When connecting and disconnecting the
batter y,alw ays obser vethe sequence of
battery clamps described. 324
324
Breakdown assistance

#
Take care toonly connect battery term i-
nals of identical polarity when receiving
starting assistance. #
Obser vethe sequence described for
connecting and disconnecting the jump
leads when receiving starting assistance. #
Do not connect or disconnect the bat-
te ry term inals while the engine is run-
ning. &
W
W ARNI NG
ARNI NGRisk of explosion due toexplo-
sive mixture of gases
An explosive mixture of gases can escape
from the battery during charging and starting
assis tance. #
Fire , naked 0ames, smoking and creating
spar ksmust be avoided. #
Make sure there is adequate ventilation. #
Do not stand overth e batter y. &
W
WARNI NG
ARNI NGRisk of explosion from a frozen
battery
A dischar ged battery may freeze at temp era-
tures slightly abo veor below freezing point.
During starting assistance or battery charging,
battery gas can be released. #
Always allow a battery tothaw before
ch arging it or per form ing starting assis-
ta nce. If
th e indicator/warning lamps in the inst rument
clus ter do not light up at low temp eratures, it is
ve ry likely that the dischar ged battery has frozen.
In this case you may neither jump-start theve hi-
cle nor charge the batter y.
The service life of a bat tery that has been thawed
may be dramatically shor tened. The starting char-
acteristics may be impaired, especially at low
te mp eratures.
It is recommended that you ha veath awe d battery
ch ecked at a quali/ed specialist workshop. All v
All v ehicles
ehicles
* NO
NOTE
TEDamage caused bynume rous or
ex tended attem ptsto start the engine Numerous or
extended attem ptsto start the
engine may damage the catalytic con verter
due tonon-combusted fuel. #
Avoid numerous and extended attem pts
to start the engine. Obser
vethefo llowing points during starting assis-
ta nce and when charging the batter y:
R Only use undamaged jump lead/charging
cables with a su1cient cross-section and
insulated term inal clamps.
R Non-insulated parts of thete rm inal clamps
must not come into contact with other me tal
parts while the jump lead/charging cable is
connected tothe battery/jump-start connec-
tion point.
R The jump lead/charging cable must not come
into contact with any parts which may mo ve
when the engine is running. Breakdown assistance
325 325

R
Always make sure that nei ther you nor the bat-
te ry is electrostatically charge d.
R Keep awa y from /re and naked 0ames.
R Do not lean overth e batter y.
Obser vethe additional following points when
ch arging the batter y:
R Only use battery charge rs tested and
appro vedfo r Mercedes-Benz.
R Read the battery charge r's operating inst ruc-
tions before charging the batter y.
Obser vethe additional following points during
starting assistance:
R Starting assis tance may only be pr ovided
using vehicles, batteries or other jump start
devices with a nominal voltage of 12 V.
R The vehicles must not touch.
R V
V ehicles wit
ehicles wit h a pe
h a petr
trol engine:
ol engine: jump-start the
ve hicle only when the engine and exhaust sys-
te m are cold. S
S
t
tar
ar ting assist
ting assist ance and c
ance and c har
harging t
ging t he 12 V batt
he 12 V batt ery
ery R R
eq eq uir
uir ements:
ements:
R The vehicle is secured with the electric par k-
ing brake.
R V
Vehicles wit
ehicles wit h aut
h automatic tr
omatic tr ansmission:
ansmission: the
transmission is in position j.
R The vehicle and all elect rical consume rsare
switched o..
R The bonnet is open. Example: engine compartment
#
Slide co ver1 of positive contact 2onthe
jump-starting connection point in the direction
of the ar row. #
Connect positive contact 2onyour vehicle
to the positive term inal of the donor battery
using the jump lead/charging cable. Alw ays326
326
Breakdown assistance

begin with positive contact
2onyour own
ve hicle /rst. #
Dur
During st
ing st ar
arting assist
ting assist ance:
ance:startthe engine of
th e donor vehicle and run at idle speed. #
Connect the negative term inal of the donor
battery and ear thpoint 3ofyour ow nve hicle
by using the jump lead/charging cable. Begin
with the donor battery /rst. #
Dur
During st
ing st ar
arting assist
ting assist ance:
ance:startthe engine of
yo ur ow nve hicle. #
Dur
During t
ing t he c
he char
harging pr
ging pr ocess:
ocess: startthech arg-
ing process. #
Dur
During st
ing st ar
arting assist
ting assist ance:
ance:letthe engines run
fo r se veral minutes. #
Dur
During st
ing st ar
arting assist
ting assist ance:
ance:before disconnect-
ing the jump lead, switch on an electrical con-
sumer on your ow nve hicle, e.g. there ar win-
dow heater or lighting.
When the starting assistance/charging process is
comple te, per form thefo llowing steps: #
Firs t, re mo vethe jump lead/charging cable
from ear thpoint 3and the negative term inal of
the donor batter y,then from positive con-
ta ct 2 and the positive term inal of the donor
batter y.Begin ea chtime with the contacts on
yo ur ow nve hicle /rst. #
ATer removing the jump lead/charging cable,
close co ver1 of positive contact 2.
Fu rther information can be obtained at a quali/ed
specialist workshop. R
R
eplacing t
eplacing t he 12 V batt
he 12 V batt ery
ery #
Obser vethe no tes on the 12 V battery
(/ page 322).
Mercedes-Benz recommends that you ha vethe
12 V battery replaced at a quali/ed specialist
wo rkshop, e.g. at a Mercedes-Benz Se rvice
Centre.
Obser vethefo llowing no tes if youwa nttoreplace
th e battery yourself:
R Alwaysre place a faulty battery with a battery
which meets the speci/c vehicle requ ire-
ments. The
vehicle is equipped with an AGMtech nol-
ogy bat tery (Absorbent Glass Mat) or a lith-
ium-ion batter y.Fu llve hicle functionality is
only guaranteed with an AGM bat tery or lith-
ium-ion batter y.Fo r saf etyre asons, Mercedes-
Benz recommends that you only use batteries
which ha vebeen tested and appro vedfo ryo ur
ve hicle byMercedes-Benz.
R Carryove r de tach able parts, such as vent
hoses, elbow /ttings or term inal co vers from
th e battery being replaced.
R Make sure that theve nt hose is alw ays con-
nected tothe original opening on the side of
th e batter y.
Fi t any existing or supplied cell caps.
Otherwise, gases or battery acid could
escape.
R Make sure that de tach able parts are recon-
nected in the same way. Breakd
own assistance
327 327

T
T
o
o w
w -st
-st ar
arting or to
ting or towing away
wing away P
P
er
er mitt
mitt edto
ed towing met
wing met hods (non plug-in h
hods (non plug-in h ybr
ybrid)
id) *
N
NOOTE
TE Damage from automatic braking If one of
thefo llowing functions is switched
on, theve hicle brakes automatically in cer tain
situations:
R Active Brake Assist
R Active Distance Assist DISTRONIC
R HOLD function
R Active Parking Assist
To avoid damage totheve hicle, deactivate
th ese systems in thefo llowing or similar situa-
tions: #
during towing #
in a car wash Mercedes-Benz
recommends transporting your
ve hicle in the case of a breakdown, rather than
to wing it away.
Fo rto wing, use a tow rope or tow bar with bo th
axles on thegr ound. Do not use tow bar systems. *
N
NO OTE
TE Damage totheve hicle due to tow-
ing awa y incor rectly #
Obser vethe inst ructions and no tes on
to wing away. V
V
ehicles wit
ehicles wit h r
h rear wheel dr
ear wheel dr ive
ive P
P
er
er mitt
mitt edto
ed towing met
wing met hods
hods
Bo th axles on
th egr ound Ye
s, maximum 50 km at
50 km/h
Fr ont axle
ra ised No
Re ar axle
ra ised Ye
s, if the steering wheel is
/xed in the centre position
with a steering wheel lock 4MA
4MA
TIC v
TIC v ehicles
ehicles P
P
er
er mitt
mitt edto
ed towing met
wing met hods
hods
Bo th axles on
th egr ound Ye
s, maximum 50 km at
50 km/h
Fr ont axle
ra ised No
Re ar axle
ra ised No T
T
o
o wing wit
wing wit h a r
h a raised axle:
aised axle: towing should be per-
fo rm ed byato wing compan y. T
T
o
o wing t
wing t he v
he vehicle wit
ehicle wit h bot
h both axles on t
h axles on t hegr
he ground
ound #
Obser vethe no tes on the permitted towing
me thods (/ page 328). #
Make sure that the battery is connected and
ch arge d.
Obser vethefo llowing points when the battery is
dischar ged:
R the engine cannot be star ted328
328
Breakdown assistance

*
N
N O
OTE
TE Damage or malfunctions caused by
moisture Moisture may cause damage
tothe electrical
system or cause it tomalfunction. #
When the fuse box is open, make sure
th at no moisture can enter the fuse box. #
When closing the fuse box, make sure
th at the seal of the lid is positioned cor-
re ctly on the fuse box. If
th e ne wlyinser ted fuse also blo ws, ha vethe
cause traced and recti/ed at a quali/ed specialist
wo rkshop.
Ensure thefo llowing before replacing a fuse:
R The vehicle is secured against rolling away.
R All electrical consume rsare switched o..
R theve hicle is switched o..
The elect rical fuses are located in various fuse
bo xes:
R Fuse box in the engine compartment on the
driver's side (/ page 333) R
Fuse box on the driver's side of the cockpit
(/ page 334)
R Fuse box in the front passenger foot we ll
(/ page 334)
R Fuse box in the boot on theright-hand side of
th eve hicle, when vie wed in the direction of
tr ave l (/ page 334) Opening and closing t
Opening and closing t
he fuse bo
he fuse box in t
x in the engine
he engine
com
com par
partment
tment R
R
eq
eq uir
uir ements:
ements:
R A dry clo thand a scr ewdriver are available.
Obser vethe no tes on elect rical fuses
(/ page 332).
Opening
Opening &
W
WARNING
ARNING Risk of injury from using the
windscreen wipers when the bonnet is
open
If th e windscreen wipers start moving when
th e bonnet is open, you could be trapped by
th e wiper linkage. #
Always switch o. the windscreen wipers
and theve hicle /r stifyo u need toopen
th e bonnet. #
Turn clips 2on co ver1 aqu arter-turn to
anti-clockwise. #
Pull co ver1 upwards in the direction of the
ar ro w. Breakd
own assistance
333
333