2012 MERCEDES-BENZ M-Class engine overheat

Cert
ainengin esyst ems aredesi gned tokeep
th eleve lof pois onous compo nentsin ex haust
fum eswit hin legal limits.
Thes esyst ems onlywork atpeak efficie ncy
when they are main tainedex act lyin
acc ordanc ewit hth eman ufacturer's
spec ifications.Fo rthis reason, allwork onthe
engine mustbecarried outonly byqual ified
and authorized Mercedes-Ben ztechn icians.
The engin esett ings must notbechanged in
any circumstan ces.Furthermor e,all specific
servic ework must becarried outatregular
int ervals andinaccor dance withthe
Mercedes- Benzservic erequirement s.Det ails
can befound inthe Serv iceBook let. Engine
oil
! Vehicles withadiesel particle filter:
If the vehic leismost lydriven forshort
distan ces,itis possible thatmalfun ctions
may occurduring theautomat icclean ingof
the diesel particle filter. This canlead to
engin edamage. Therefore,ifyou frequen tly
drive short distan ces,make suretodrive
on highways orinter- urban roadsfor20
minut esatleast every 310miles (500km). Br
akes
Imp ortant safet ynotes G
WARN
ING On
slippery roadsurfac es,nev erdowns hiftin
order toobtain brakingact ion. This could
result indrive wheel slipand reduce dvehic le
con trol. Your vehic le'sABSwill notpreve nt
this type ofloss ofcon trol. G
WARN
ING Make
surethatyoudonot endan gerother
road users whenyouapply thebrake s. Downhill
gradient s !
Onlong andsteep gradien ts,you must
reduce theload onthe brake sby shift ing
early toalower gear.Thisallows youtotak e
advant ageofthe engin ebrakin geffe ctand
helps avoidoverheatin gand excessive
wear ofthe brake s.
When youtakeadvant ageofthe engin e
brakin geffe ct,a drive wheel maynotturn
for some time,e.g. onaslippery road
surfac e.This could cause damage tothe
drive train. This type ofdamage isnot
cov ered bythe Merc edes- Benzwarrant y.
Hea vyand lightload s G
WAR
NING De
pre ssin gth ebrak epedal constant lyres ults
in ex ces siveand premat urewear tothebrak e
pads.
It may alsocauseth ebrak estoove rheat,
ser iously impairingth eir effect iven ess.Itm ay
th en notb epossible tostop thevehicle in
sufficien ttime toavoid anacciden t.
If the brakes havebeen subject edtoaheavy
load, donot stop thevehicle immediately, but
drive onfor ashort while. Thisallows the
airflow tocool thebrakes morequickly.
Wet roads G
WARN
ING Aft
erdriving inheavy rainforsome time
without applying thebrakes orthro ugh water
deep enough towet brake compon ents,the
first braking actionmaybesomewhat
reduced. Youhave todepress thebrake pedal
more firmly. Maintain asafe distanc efrom
vehicles infron t.
Aft erdriving onawet road orhaving the
vehicle washed, brakefirmlywhilepaying
atten tiontothe traff iccon ditions .This will
warm upthe brake discs, thereby dryingthem
more quickly andprotec tingthem against
corr osion. Driving
tips
159Driving and parking Z

This
style ofdriving prevent s:
R the vehicle fromlifting offthe ground onthe
brow ofahill
R the vehicle fromtraveling tooquickly down
the other side
Driving downhill R
Drive slowly.
R Do not drive atan angle down steep
inclines. Steer into theline offall and drive
with thefron twheels aligned straight.
Otherwise, thevehicle couldslipsidewa ys,
tip and rollover.
R Before tackling steepdownhill gradients,
select shiftrange 1.
R Act ivate DSR. Ifthis isnot sufficient, brake
gently. Whendoingso,make surethatthe
vehicle isfacing inthe direction ofthe line
of fall.
R Check thatthebrakes areworking normally
after along downhill stretch. i
The
special off-road ABS settin genables
a precise, briefandrepeated lockingofthe
front wheels, causing themtodig into the
loose earth. Beaware thatthefront wheels
easily skidacross theground surface if
completely brakedandtherefore losetheir
abili tyto steer. Driving
systems Cruise
control
Import antsafety notes G
WARNING The
cruise controlisaconven iencesystem
designed toassist thedriver during vehicle
operation. Thedriver isand must always
remain responsible forthe vehicle's speed
and forsafe brake operation.
Only usethecruise controlifthe road, traffic,
and weather condition smake itadvisabl eto
travel ataconst antspeed. R
The useofthe cruise controlcan be
dangerous onwinding roadsorinheavy
traffic because condition sdo not allow safe
driving ataconst antspeed.
R The useofthe cruise controlcan be
dangerous onslippery roads.Rapid
changes intire tract ioncan result inwheel
spin andloss ofcont rol.
R Deactivate thecruise controlwhen driving
in fog.
The "Resu me"funct ionshould onlybe
operated ifthe driver isfully aware ofthe
previously setspeed andwishes toresume
this particular presetspeed. G
WARNING The
cruise controlbrakes automatically so
that thesetspeed isnot exceeded.
General notes Cruise
controlmaintains aconst antroad
speed foryou. Itbrakes automatically inorder
to avoid exceeding thesetspeed. Onlong and
steep downhill gradients, especiallyif the
vehicle isladen ortowing atrailer, youmust
select shiftrange 1,2or 3in good time. By
doing so,you willmake useofthe braking
effect ofthe engine, whichrelieves theload
on the brake system andprevents thebrakes
from overheating andwearing tooquickly.
Use cruise controlonly ifroad andtraffic
condition smake itappropriate tomaintain a
steady speedforaprolonged period.Youcan
set any road speed above20mph
(30 km/h). i
Cruise
controlshould notbeactivated
during off-road driving. Driving
systems
167Driving and parking Z

G
WARNING An
intermittent warningsound sand the
dista ncewarning lamp · inthe instrument
cluster isillumina tedifthe DISTRONIC PLUS
system calculates thatthedista ncetothe
vehicl eahe adand yourvehicle's current
speed indicat ethat theDISTRONIC PLUSwill
not becapable ofslowing thevehicle
sufficien tlytomaint ainthe preset following
distanc e,which createsadanger ofa
collision.
Immediately brakethevehicle toincr ease
your distanc eto the precedin gvehicle. The
warning soundisinten dedasafinal caution
in which youshould intercede withyour own
braking inputstoavoid apoten tially
dangerous situation.Donot wait forthe
operation ofthe warning signaltointerc ede
with your ownbraking. Thiswillresult in
potent iallydangerous emergencybraking
which willnotalway sresult inan impact being
avoided.
Tailgating increasestherisk ofan accident . G
WARNING DIS
TRONIC PLUSbrakes yourvehicle witha
maximum deceleration of13 ft/s2
(4 m/s 2
).
This isequivalent toapproximately 40%of
your vehicle's maximum possible
deceleration.
You need tobrake yourself toprevent a
collision. DISTRONIC PLUSbrakes thevehicle
to restore thesetdistance fromthevehicle
ahead orthe setspeed. G
WARNING If
you donot receive visualoracoustic
warning signalsduringacritic altraffic
situation, DISTRONIC PLUShaseither not
recogn izedthecollision risk,hasbeen
deactivated orismalfunct ioning.
Remember, whetherornot DISTRONIC PLUS
is operating, itis ultimately alwaysthe drivers
responsibility toapply thebrakes inorder to
cont rolthe vehicle andavoid acollision. G
WARNING The
vehicle canbebraked whenDISTRONIC
PLUS isactivated. Forthis reason, deactivate
DIS TRONIC PLUSifthe vehicle isto be set in
motion byother means (e.g.inacar wash or
by towing).
If you want DISTRONIC PLUStoassist you,
the radar sensor system mustbeactivated
(Y page 236)andoperational.
General notes DIS
TRONIC PLUSregulates thespeed and
automatically helpsyoumaintain the
distance tothe vehicle detectedinfront .It
brakes automatically inorder toavoid
exceeding thesetspeed.
On long andsteep downhill gradients,
especially ifthe vehicle isladen ortowing a
trailer, youmust select shiftrange 1,2or 3
in good time. Bydoing so,you willmake use
of the braking effectofthe engine, which
relieves theload onthe brake system and
prevent sthe brakes fromoverheating and
wearing tooquickly.
If aslower-moving vehicleisdetect edinfront ,
DIS TRONIC PLUScauses yourvehicle to
brake andmaintain thepreset distance tothe
vehicle infront .
If there isno vehicle drivinginfront ofyou,
DIS TRONIC PLUSfunctionslikecruise
cont rolataspeed rangebetween 20mph
(Canada :30 km/ h)and 120 mph
(Canada :200 km/h).If avehicle isdriving in
front ofyou, itfunct ionsataspeed range
between 0mph (0km/ h)and 120 mph
(Canada :200 km/h).
Do not use DISTRONIC PLUSwhiledriving on
roads withsteep gradients.
As DIS TRONIC PLUStransmitsradar waves,
it can resemble theradar detect orsofthe
responsible authorities.Youcanrefer tothe
applicabl esection inthe Operator's Manualif
there areany questions concerning this. i
USA
only: Driving
systems
171Driving and parking Z

Please
notethat when towing atrailer,
PARKTRONIC (Ypage 183)andBlind Spot
Assist (Ypage 198)areonly availabl ewith
limitations ,or not atall. i
On
vehicles withoutlevelcontrol,the
height ofthe ball coupling willalter
accordin gto the load placed onthe vehicle.
If necess ary,useatrailer withaheight-
adjustable drawbar.
Driving tips i
Observe
theinform ationonESP®
trailer
stabilization (Ypage 64)and onpulling
away withatrailer. (Ypage 141).
The maximum permissible speedforvehicle/
trailer combinat ionsdepends onthe type of
trailer. Before beginnin gthe journ ey,check
the trailer's document sto see what the
maximum permittedspeed is.Observe the
legally prescribed maximumspeedinthe
relevant country.
For cert ainMercedes- Benzvehicles, the
maximum permissible rearaxle load is
incr eased whentowing atrailer. Refertothe
"Technical data"sectiontofind outwhether
this applies toyour vehicle. Ifyou utilize any
of the added maximum rearaxle load when
towing atrailer, thevehicle/t railer
combinat ionmay notexceed amaximum
speed of60 mph(100 km/h)for reasons
conc ernin gthe operating permit.Thisalso
applies incount riesinwhich thepermissible
maximum speedforvehicle/t railer
combinat ionsisabove 60mph(100 km/h).
When towing atrailer, yourvehicle's handling
charact eristics willbedifferen tinc omparison
with when driving without atrail er.
On long andsteep downhill gradients, you
must selectshift range 1,2or 3in good time. i
This
alsoapp liesif you have activated
cruise control orDISTRONIC PLUS.
This willuse thebraking effectofthe engine,
so that lessbraking willbe requ iredto
maintai nthe speed. Thisrelieves theload on
the brake system andprevents thebrakes from
overheating andwearing tooquickly. If
you need additional braking,depressthe
brake pedalrepeatedly ratherthan
cont inuously .
Driving tips R
Maintain agreater distance fromthe
vehicle infront thanwhen driving without a
trailer.
R Avoid braking abruptly. Ifpossible, brake
gently atfirst toallow thetrailer torun on.
Then, increase thebraking forcerapidly .
R The values givenforgradient-c limbing
capabil itiesfrom astandst illrefer tosea
level. When driving inmountainous areas,
note thatthepower output ofthe engine,
and consequent lythe vehicle's gradient-
climbing capability,decrease with
increasing altitude.
If the trailer swings fromsidetoside:
X Do not accelerate.
X Do not counter- steer.
X Brake ifnecessary. Assemblin
gthe ball coupling
! Mercedes-Ben zrecomm endsthatyou
have theball coupling assembled ata
qualified specialist workshop.Only a
qualified specialist workshophas the
nec essary specialist knowledge andtools
to carry outthework required. Youcould
other wiseincorrectlyassemble theball
coupling ortight enthe nut with the
incor recttorque. Thiscould leadtothe ball
coupling andtheball coupling carrier
becomin gdetached whiletowing atrailer.
As aresult, youcould cause anacciden t.
Therefor e,have theball coupling
assembled ataqualified specialist
worksho p.
If the assembled ballcoupling hasbeen
permanen tlymount edon the vehicle, have
the ball coupling regularly checkedfor 212
Tr
ailer towingDriving and parking

brake
usingthebrake controller, andchec k
the brakes forcorr ectfunc tion.
R Sec ureany objec tson the trailer topreven t
the cargo fromslipping whenthevehicle is
in mot ion.
R Ifyou couple upatrailer, regularly check
the cargo forsecure fasteningand make
sure thatthetrailer lamps and(if
applicable) thetrailer brakes are
func tioningcorr ectly.
R Bear inmind thatthehandling willbeless
stable whentowingatrailer thanwhen
drivin gwithout one.Avoid sudden steering
movem ents.
R The vehicle/ trailercombin ationisheavier,
acceler atesmore slowly, hasadecreased
gradient climbingcapability andalonger
brakin gdistan ce.
It is more suscept ibletoside winds and
requires morecareful steering.
R Ifpossible, avoidabrupt braking.Depres s
the brake pedalmoderat elyatfirst ,so that
the trailer canactiv ateitsown brakes. Then
incr ease thepressure onthe brake pedal.
R Ifthe automatic transmission continues to
shift back andforthbetween twogears
when drivingup ordownhill, restrict the
shift range. Selectshiftrange 4,3,2,or 1.
Al ower gearandlower speed reduce the
risk ofengine failure.
R On long andsteep gradients thatare
difficult todrive down inshift range 1,
switch tothe off-road program orengage
the LOW GEAR off-road gear.
R When driving downhill, shifttoalower gear
to utilize theengine's brakingeffect.
Avoid continuous brakeapplication asthis
may overheat thevehicle brakesand,if
installed, thetrailer brakes.
R Ifthe coolant temperat ureincreases
dramatically whiletheair-con ditioning
system isswitched on,switch offthe air-
condit ioning system.
Coolant heatcanadditionally bedissipated
by opening thewindows andbysett ingthe blower
fanand theinterior temperat ureto
maximum.
R When overtak ing,payparticular attention
to the exten dedlength ofyour vehicle/
trailer combinat ion.
Due tothe length ofyour vehicle/t railer
combinat ion,youwillhave totravel an
additional distancebeyondthevehicle you
are overtak ingbefore returningtothe
previous lane. Deco
upling atrail er G
WA
RNI NG Ve
hicle swi th airs uspen sionprogram :While
you arecoupling ordecoupling atrailer, make
sure nobody locksorunlocks thevehicle and/
or opens orcloses doorsorthe tailgate.
The vehicle's levelcould change andyou
could endanger yourselfand/orothersasa
result.
Make surethatyoudonot operate theADS
switch orthe vehicle levelcontrolsystem
when coupling/decoupling thetrailer.
! Donot disconnec ta trailer withan
engaged overrunbrake.Otherwise, your
vehicle couldbedamaged bythe
rebounding ofthe overrun brake.
X Make surethattheautomatic transmission
is set toposition P.
X Apply thevehicle's electricparking brake.
X Start theengine.
X Close alldoors andthetailgate.
X Apply thetrailer's parkingbrake. G
WARNING Vehicles
withairsuspension program:As
soon asyou disconnec tthe electrical
conn ection between thetrailer andthe
vehicle, thevehicle willlower. Tohelp avoid
personal injury,makesurenoone isnear the
wheel housing orunderneath thevehicle
before theelectrical connection is
disconnec ted. Tr
ailer towing
217Driving and parking
Z

Useful
information
i This
Operat or'sManual describesall
models andallstan dard andoption al
equipment ofyour vehicle available atthe
time ofpublication ofthe Operat or's
Manual. Country-specificdiffer encesare
possible. Pleasenotethat your vehicle may
not beequipped withallfeature s
descr ibed. Thisalso applies tosafet y-
related systemsand func tions. i
Please
readtheinfor mation onqualified
specialist workshops(Ypage 25). Impor
tant safet ynotes You
willfind anillustrat ionofthe instrumen t
clust erinthe "Ataglance" section
(Y page 29). G
WARN
ING A
driver' satt ent ion tothe road andtraffic
con dition smust always behis/her primary
focus whendriving.
For your safetyand thesafet yof other s,
select ingfeature sthr ough themultifun ction
steer ingwheel should onlybedone bythe
driver whentrafficand road condition spermit
it to be done safely.
Bear inmind thatataspeed ofjust 30mph
(approxim ately50km/ h),your vehic leis
cove ringadistan ceof44 feet (approxim ately
14 m)every second. G
WARN
ING No
messages willbedisplayed ifeither the
inst rumen tclust eror the multif unction
display isinoper ative.
As aresult, youwillnotbeable tosee
info rmat ionabout yourdrivin gcon dition s,
such as
R speed
R outside temperatur e
R warnin g/indicato rlamps R
malf unction/ warn ingmes sages
R failur eof any systems
Dr ivin gch arac terist ics may beimpair ed.
If you must continue todriv e,do sowith added
caut ion.Contac tana uth oriz edMer cedes-
Ben zCent eras soon aspossible. G
WARN
ING Malfunct
ionand warning messages areonly
indicat edfor cert ainsystems andare
inten tionally notvery detailed. The
malfunct ionand warning messages are
simply areminder withrespect tothe
operation ofcert ainsystems. Theydonot
replace theowner's and/ordriver's
respons ibilitytomaint ainthe vehicle's
operatin gsafety. Haveallrequired
maint enanc eand safety checksperform edon
the vehicle. Bringthe vehicle toan authorized
Mercedes- BenzCenter toaddress the
malfunct ionand warning messages. Displays
andopera tion Coolant
temperaturedispla y G
WARN
ING Drivin
gwhen yourengine isoverheat edcan
cause somefluidswhich mayhave leaked into
the engine compart menttocatc hfire. You
could beseriously burned.
St eam from anoverheat edengine cancause
serious burnswhich canoccur justbyopening
the engine hood.Stay away fromtheengine
if you seeorhear steam comingfrom it.
St op the vehicle inasafe location awayfrom
other traffic.Turn offthe engine, getout ofthe
vehicle anddonot stand nearthevehicle until
the engine hascooled down.
The coolant temperaturegauge isin the
inst rument clusteronthe right- hand side.
Under normaloperatin gcon ditions andwith
the specified coolantlevel,thecoolant
temper aturemayriseto248 ‡(120 †). 222
Displays
andopera tionOn-board computer and displays

Disp
laymessa ges Poss
iblecauses/c onseq uences and M Solu
tions ?
Coo
lantLev elLow Sto
pVeh icl eTur n Eng
ine Off The
coolan tistoo hot.
X Pull over andstop thevehicle safelyandswitch offthe engine,
pay ing attent iontoroad andtraffic conditions.
X Make surethattheairsuppl yto the engine radiatorisnot
blocked, e.g.bysnow, slushorice.
X Wait untilthedispla ymessage disappearsbefore restarting the
engine. Otherwise, thereisarisk ofengine damage .
X Pay attent iontothe coolant temperature display.
X Ifthe temperature increasesagain,visit aqual ified speciali st
workshop immediately . The
poly-V-belt mayhave torn.
X Pull over andstop thevehicle safelyandswitch offthe engine,
pay ing attent iontoroad andtraffic conditions.
X Open thehood.
X Check whether thepoly-V-belt istorn.
If the poly-V-belt istorn:
! Donot cont inue driving. Theengine couldotherwise overheat.
X Consult aqual ified speciali stworkshop.
If the poly-V-belt isnot dam aged:
X Wait untilthedispla ymessage disappearsbefore restarting the
engine. Otherwise, thereisarisk ofengine damage .
X Pay attent iontothe coolant temperature display.
X Visit aqual ified speciali stworkshop. G
WARNING Driving
whenyourengine isoverheated cancause somefluidswhich mayhave leaked intothe
engine compartment tocatch fire.Youcould beseriously burned.
Steam fromanoverheated enginecancause serious burnswhich canoccur justbyopening the
engine hood.Stayawayfrom theengine ifyou seeorhear steam coming fromit.
Stop thevehicle inasafe location awayfrom other traffic. Turnoffthe engine, getout ofthe
vehicle anddonot stand nearthevehicle untiltheengine hascooled down.
! Ifthe coolant temperature exceeds248‡(120 †)donot cont inue driving. Theengine will
otherwise bedamage d. Dis
play messages
255On-board computer and displays Z

Disp
laymessa ges Poss
iblecauses/c onseq uences and M Solu
tions ? The
engin efan isdef ective.
X At coolan ttemperatures under248‡(120 †),drive tothe next
qualified specialist workshop.
X Avo idsubjec tingthe engin etoheavy loads, e.g.driving in
mountainous terrain,andstop- and-go traffic. # The
battery isnot being charged.
Possible causesare:
R adefectiv ealternator
R atorn poly-V-belt
R amalfunct ioninthe electron ics
X Pull over andstop thevehicle safelyandswitch offthe engine,
paying attentiontoroad andtraffic conditions.
X Open thehood.
X Check whether thepoly-V-belt istorn .
If the poly-V- beltistorn:
! Donot cont inue driving. Theengine couldotherwise overheat.
X Consult aquali fiedspecialist workshop.
If the poly-V- beltisnot dam aged:
X Visit aquali fiedspecialist workshop. 4
Check
Engine Oil At
Next Refueling The
engine oillevel hasdropped tothe minimum level.
Aw arning tone also soun ds.
X Chec kthe engine oillevel atthe latest whennextrefueling
(Y page 313).
X Ifnecessary, addengine oil(Ypage 314).
X Ifengine oilneeds tobe added moreoften thanusual,have the
engine checkedataqual ified specialist workshop. Inform
ationonapproved engineoilscan beobtained fromanyqual ified specialist workshop
or on the Internet athttp: //www.mbusa.com (USAonly).
! The oillevel istoo low. Avoid longjourneys withtoolittle engine oil.There isarisk of
engine damage.
The displa ymessages andthecorresponding symbolthatindicate thattheoillevel istoo
low must notbeignored. 256
Display
messagesOn-board computer and displays