engine MERCEDES-BENZ S-CLASS SALOON LONG 2020 Repair Manual

R
frequent operation in mountainous terrain or
on poor road sur faces
R when the engine is of ten le ftidling for long
periods
R operation in particula rly dusty conditions
and/or if air-recirculation mode is frequently
used
In these or similar operating conditions, ha vethe
interior air filter, engine air cleaner, engine oil
and oil filter etc. changed more frequent ly. The
tyres must be checked more frequently if the
ve hicle is operated under increased loads. Fur‐
th er information can be obtained at a qualified
specialist workshop. Battery disconnection periods
The ASS
YST PLUS service inter val display can
calculate the service due date only when the
battery is connec ted. #
Display the service due date on the driver
display and no teit down before disconnect‐
ing the battery (/ page 347). Engine compartment
Ac
tive bonn et(pedestrian pr otection) Operation of
the active bonnet (pedestrian
pr otection)
In cer tain accident situations, the actuation of
th e active bonn etreduces therisk of injury to
pedestrians. The rear area of the bonn etis
ra ised byappr oximately 80 mm.
Af ter being triggered, the active bonn etremains
in thera ised position. Limited visibility due to
th era ised bonn etcannot be ruled out.
Af terth e active bonn ethas been actuated,
pedestrian pr otection may be limited.
Ha ve the full functionality of the active bonn et
re stored immediately in a qualified specialist
wo rkshop.
If necessar y,adjust your seat position and drive
carefully toaqu alified specialist workshop. If a
safe continued journey is not possible, contact a
qu alified specialist workshop. Opening and closing
the bonnet &
WARNING Risk of accident due todriv‐
ing with the bonn etunlo cked
The bonn etmay open and block your vie w. #
Neverre lease the 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 bonn et
The bonnet 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. #
Do not open or close the bonn etifth ere
is a person in the bonn et's range of
mo vement. 348
Maintenance and care

&
WARNING Risk of bu rns when opening
th e bonn et
If yo u open the bonn etwhen the engine has
ove rheated or when there is a fire inthe
engine compartment, thefo llowing situations
may occur:
R You could come into contact with hot
ga ses.
R You could come into contact with other
hot, escaping operating fluids. #
Before opening the bonn et, allow the
engine tocool down. #
Intheeve nt of a fire inthe engine com‐
partment, keep the bonn etclosed and
call thefire service. &
WARNING Risk of inju rydue tomoving
parts
Components in the engine compartment may
continue running or start up sudden ly,even if
th e ignition is switched off. Make sure of
thefo llowing before per form ing
ta sks in the engine compartmen t: #
Switch the ignition off. #
Neverre ach into the danger zone sur‐
ro unding moving co mponents, e.g. the
ro tation area of thefa n. #
Remo vejewe llery and watches. #
Keep items of clo thing and hair away
from moving parts. &
WARNING Risk of inju ryfrom touching
co mp onents under voltage
The ignition sy stem and the fuel injection
sy stem workunder high voltage. You could
re cei 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 component parts in the engine com‐
partment can be very hot, e.g. the engine,
th e cooler and parts of theex haust sy stem. #
Allow the engine tocool down and only
to uch co mponent parts described in
th efo 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. Maintenance and care
349

Opening
the bonnet #
Pull on handle 1twice.
The bonnet will be released and open
slight ly. #
Then lift the bonn etby hand. Closing
the bonnet
* NO
TEDama getothe bonn et If
th e bonn etis closed manuall y,there is a
ri sk of dents. #
Do not close the bonn etmanually. #
Lowe rth e bonn etto a height of around
20 cm and then allow it tofall, applying a lit‐
tle forc e as you let it go. #
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 with the driver
display
Re quirements:
R The engine has been warmed up.
R The vehicle is par ked on a le vel sur face.
R The engine is running at idle speed.
R The bonnet is closed. The 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.
Driver display: 4 Service
The engine oil le vel is shown.
One of thefo llowing messages will appear on
th e driver display:
R Engine oil level Measuring now… : measure‐
ment of the oil le vel is not yet possible. #
Repeat there qu est af ter a maximum of
30 minutes' driving.
R Engine oil level OK andthe bar display for
indicating the oil le vel on the driver display is
green and is between "min" and "max": the
oil le vel is cor rect.
R Engine oil level Top up 1,0 l andthe bar dis‐
play for indicating the oil le vel on the driver
display is yellow and is below "min": #
Add 1 l of engine oil. 350
Maintenance and care

R
Engine oil level Reduce andthe bar display
fo r indicating the oil le vel on the driver dis‐
play is yellow and is abo ve"max": #
Drain off any excess engine oil that has been
added. Todo so, consult a qualified specialist
wo rkshop.
R For engine oil level switch on ignition #
Switch on the ignition tocheck the engine oil
le ve l.
R Engine oil level System inoperative : The oil
le ve l sensor is defective or not connec ted. #
Consult a qualified specialist workshop.
R Engine oil level currently inoperative #
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 component parts in the engine com‐
partment can be very hot, e.g. the engine,
th e cooler and parts of theex haust sy stem. #
Allow the engine tocool down and only
to uch co mponent parts described in
th efo llowing. &
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. #
Follow the instructions on the service
inter val display forch anging the engine
oil and obser vethe prescribed change
inter vals. #
Do not use additives. *
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. %
Depending on driving style, theve hicle con‐
sumes up to0.8 litr e of oil pe r10 00 km. The
oil consum ption may be higher than this
when theve hicle is new or if you frequently
drive at high engine speeds.
% Depending on the engine, the cap may be
ins talled in the engine compartment in dif‐
fe re nt locations. Maintenance and care
351

#
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 350). Checking
the coolant le vel &
WARNING Risk of bu rns from hot com‐
ponent parts in the engine compartment
Cer tain component parts in the engine com‐
partment can be very hot, e.g. the engine,
th e cooler and parts of theex haust sy stem. #
Allow the engine tocool down and only
to uch co mponent parts described in
th efo llowing. &
WARNING Risk of scalding from hot
coolant
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
gl ove s and saf etygl asses. #
Open the cap slowly torelease pres‐
sure. #
Only ha vethe coolant checked or refilled at a
qu alified specialist workshop. To
pping up the windsc reen washer sy stem &
WARNING Risk of bu rns from hot com‐
ponent parts in the engine compartment
Cer tain component parts in the engine com‐
partment can be very hot, e.g. the engine,
th e cooler and parts of theex haust sy stem. #
Allow the engine tocool down and only
to uch co mponent parts described in
th efo llowing. &
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. 352
Maintenance and care

R
obser vethe information on the cor rect dis‐
ta nce in the equipment manufacturer's oper‐
ating instructions.
R do not direct the nozzle of the high-pressure
cleaner directly at sensitive parts, e.g. tyres,
ga ps, elect rical components, batteries, light
sou rces and ventilation slits. Wa
shing theve hicle byhand *
NO
TEEngine dama gedue towater
ingress #
Take care not topoint thewate r jet
directly towa rdsth e air inlet grille below
th e bonn et. obser
vethe legal requ irements, e.g. in a number
of countries, washing byhand is only permitted
in specially designated wash ba ys. #
Use a mild cleaning agent, e.g. car shampoo. #
Washtheve hicle with luk ewarmwate r using
a soft car sponge. When doing so, do not
ex pose theve hicle todirect sunlight. #
Carefully hose theve hicle off with water and
dry using a chamois.
% Obse rveth e no tes on the care of car parts
(/ page 356). Note
s on paint work/matt finish paint work
care Obse
rveth e no tes on cleaning and care toavo id
damaging the paintwork and inter fering wi th the
driver assis tance sy stems.
Pa int
R Insect remains: soak with insect remo ver and
ri nse off the treated areas af terw ards.
R Bird droppings: soak with water and rinse off
af te rw ards.
R Tree resin, oils, fuels and greases: remo veby
ru bbing gently wi tha clo thsoaked in petro‐
leum ether or lighter fluid.
R Coolant and brake fluid: remo vewith a damp
clo thand clean water.
R Tarst ains: use tar remo ver.
R Wax: use silicone remo ver. R
Do not attach sticke rs,fi lms or similar mate‐
ri als. On ly havefilm attached tothe bumper
at a qualified specialist workshop.
R Remo vedirt immediatel y,where possible.
Matt finish
R Only use care products appr ovedfor
Mercedes-Benz.
R Do not attach sticke rs,fi lms or similar mate‐
ri als. On lyha ve film attached tothe bumper
at a qualified specialist workshop.
R Do not polish theve hicle and light-alloy
wheels.
R Only use car washes that cor respond tothe
latest engineering standards.
R Do not use car wash programmes with a final
hot wax treatment.
R Do not use paint cleane rs, buf fing or polish‐
ing products, gloss preser vers, e.g. wax.
In theev ent of paintwork damage:
R Alw ays ha vepaintwork repairs car ried out at
a qu alified specialist workshop. Maintenance and care
355

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 charging
th e12 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 restriction of the maximum charging
vo ltage, the battery or the on-board electron‐
ics can be damaged. #
Only use battery charge rs with a maxi‐
mum charging voltage of 14.8 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.
* NO
TEDama getothe battery from over‐
vo ltage When
charging using a bat tery charge r with‐
out a restriction of the maximum charging
vo ltage, the battery or the on-board electron‐
ics can 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
There is a danger of hydrogen gas igniting
when charging the battery if there is a short
circuit or spar ksstart toform. #
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. #
The described order of the battery
clamps must be obser ved when con‐
necting and disconnecting the batter y. #
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. 37 0
Breakdown assis tance

&
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 there is suf ficient ventila‐
tion. #
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 can be released. #
Alw ays allow a battery tothaw before
ch arging it or per form ing starting assis‐
ta nce. 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.
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. Breakdown assis
tance 371

Obser
vethe additional following points during
st arting assistance:
R Starting assis tance may only be pr ovided
using vehicles, batteries or other jump start
devices with a nominal voltage of 12V.
R The vehicles must not touch.
R Vehicles with a petrol engine: jump-start
th eve hicle only when the engine and exhaust
sy stem are cold. St
arting assi stance and charging the12 V
battery Preparing
starting assi stance/the charging
process #
Secure theve hicle byapplying the electric
parking brake. #
Select transmission position j.#
Switch off the ignition and all electrical con‐
sumers. #
Open the bonn et. #
Open co ver1. #
Slide pr otective co ver2 of positive contact
3 onthe jump-s tarting connection point in
th e direction of the ar row. St
arting assi stance #
Connect the positive conta cts oftheve hicles
with the jump lead. Start with your ow nve hi‐
cle firs t. #
Start the engine of the donor vehicle and run
it at idling speed. #
Connect negative term inal 4ofthe donor
battery tothe ear thpoint of your vehicle 372
Breakdown assis tance

using
the jump lead. Start with the donor
ve hicle firs t. #
Start the engine of your ow nve hicle. #
Let the engines runfo r se veral minutes. #
Before disconnecting the jump leads, switch
on an electrical consumer in your ow nve hi‐
cle, e.g. there ar wind owheater or the light‐
ing.
When starting assistance has finished: #
Firstremo vethe jump lead from the ear th
point of your ow nve hicle and the negative
te rm inal of the donor batter y,then remo ve
th e jump lead from the positive conta cts of
bo th vehicles. Alw aysst art with your own
ve hicle firs t. #
Close pr otective co ver2 of positive contact
3 and close co ver1.
Fu rther information can be obtained at a quali‐
fi ed specialist workshop. Charging
the12 V battery #
Connect the positive conta cts oftheve hicle
and thech arge r with thech arging cable.
St art with theve hicle firs t. #
Connect the negative conta ct ofthech arger
and ear thpoint 4ontheve hicle with the
ch arging cable. Start with thech arge rfirs t. #
Start thech arging process.
When thech arging process is comple te: #
Remo vethech arging cable from ear thpoint
4 ontheve hicle and the negative conta ct
of thech arge rfirs t and then from the posi‐
tive conta cts ontheve hicle and charge r.
Alw aysst art with theve hicle firs t. #
Close pr otective co ver2 of positive contact
3 and close co ver1. Re
placing the 12V battery #
Obser vethe no tes on the12 V battery
(/ page 368).
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
only guaranteed with an AGM battery or lith‐
ium-ion batter y.Fo r saf etyre asons,
Mercedes-Benz recommends that you on ly
use bat teries which ha vebeen tested and
appr ovedfo ryo ur vehicle byMercedes-Benz.
R Carryove r de tach able parts, such as vent
hoses, elbow fittings or term inal co vers from
th e battery being replaced.
R Make sure that theve nt hose is al ways con‐
nected tothe original opening on the side of
th e batter y.
Fit any existing or supplied cell caps.
Otherwise, gases or battery acid could
escape. Breakdown assis
tance 373