water pump MERCEDES-BENZ R320 2008 W251 Owner's Manual

444 Practical hints
What to do if …
Symbol messages
Display symbolDisplay messagePossible cause/consequencePossible solution
òReplace air filter.The air filter is clogged.Have the air filter checked by an autho-
rized Mercedes-Benz Light Truck Center.
#The battery is no longer charg-
ing.
Possible causes:

alternator malfunctioning

broken poly-V-belt
Do not forget that the brake
system requires electrical
energy and may be operating
with restricted capability.
Considerably greater brake
pedal force is required and the
stopping distance is increased.
Stop the vehicle in a safe location or as
soon as it is safe to do so and check the
poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise
the engine will overheat due to an
inoperative water pump which may
result in damage to the engine.
Contact an authorized
Mercedes-Benz Light Truck Center.
If it is intact:
Contact an authorized
Mercedes-Benz Light Truck Center
immediately. Adjust driving to be
consistent with reduced braking
responsiveness.

448 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
•Coolant Level
Stop car, switch engine off.The coolant is too hot.
Among other possible causes
(the cooling fan could be
malfunctioning), the poly-V-belt
could be broken.Stop the vehicle in a safe location or
as soon as it is safe to do so.
Turn off the engine.
Apply the parking brake (page 65).
Check the poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise
the engine will overheat due to an
inoperative water pump which may
result in damage to the engine.
Contact an authorized
Mercedes-Benz Light Truck Center.
If it is intact:
Wait for the message to disappear
before restarting the engine.
Doing otherwise could result in seri-
ous engine damage that is not
covered by the Mercedes-Benz
Limited Warranty.
(Continued on next page)

550 Index
Drinking and driving 339
Driving 50
Abroad 348
Hydroplaning 344
In winter 346, 398
Instructions 50, 339
Problems 62
Safety systems 99
Systems 257
Through standing water 347
With Distronic* 273
Driving off 56
Driving safety systems
ABS 99
BAS 101
EBP 105
ESP
®101
ETS/4-ETS 103
Driving systems 257
AIRMATIC* 276
Cruise control 257
Distronic* (Canada only) 262
Parktronic* 281
Rear view camera* 285
Driving tips 197
Kickdown 197E
Easy-entry/exit feature* 128
Control system 184
EBP 105
Indicator and warning lamps 416
Electric air pump 499
Electrical fuses see Fuses
Electrical system, Technical data 533
Electronic Brake Proportioning see EBP
Electronic Stability Program see ESP
®
Electronic Traction System see ETS/4-ETS
Emergency calls
Tele Aid* 323
Emergency, In case of
Battery, Jump starting 511
First aid kit 467
Flat tire 492
Fuses 518
Hazard warning flasher 150
Instrument cluster, Indicator
lamps 414–422
Roadside Assistance 12, 325
Towing the vehicle 513Emergency operation
Locking/unlocking the vehicle 474
Remote door unlock, Tele Aid* 328
Tailgate, Opening from the
inside 120
Emergency operation (Limp-Home
Mode) 202
Emergency tensioning device see ETD
Emission control 350
Information label 525
System warranties 10
Engine
Belt layout 526
Break-in recommendations 338
Cleaning 405
Compartment 356
Malfunction indicator lamp 29, 417
Maximum engine speed 155, 527
Number 525
Starting 53
Tachometer 29, 155
Technical data 527
Turning off 66