2001 MERCEDES-BENZ C320 engine overheat

124 Flexible service system
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Coolant temperature gauge
Turn the electronic key in starter switch to position 1
or 2.
Call up the trip odometer and main odometer by
pressing button è or ÿ on the multifunction
steering wheel. See page 96.
Press button j or k until the coolant
temperature gauge appears.During severe operating conditions and stop-and-go city
traffic, the coolant temperature may rise close to 120
°C.
The engine should not be operated with the coolant
temperature above 120
°C. Doing so may cause serious
engine damage which is not covered by the
Mercedes-Benz Limited Warranty.
Note:
Excessive coolant temperatures trigger a warning in the
multifunction display. See page 282.
P54.30-3605-26
Wa r n i n g !
• Driving when your engine is badly overheated
can cause some fluids which may have leaked
into the engine compartment to catch fire. You
could be seriously burned.• Steam from an overheated engine can cause
serious burns and can occur just by opening
the engine hood. Stay away from the engine if
you see or hear steam coming from it.Turn off the engine, get out of the vehicle and do
not stand near the vehicle until it cools down.

228 Catalytic converter
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Catalytic converter
Your Mercedes-Benz is equipped with monolithic type
catalytic converters, an important element in
conjunction with the oxygen sensors to achieve
substantial control of the pollutants in the exhaust
emissions. Keep your vehicle in proper operating
condition by following our recommended maintenance
instructions as outlined in your Service Booklet.
Caution!
To prevent damage to the catalytic converters, use only
premium unleaded gasoline in this vehicle.
Any noticeable irregularities in engine operation should
be repaired promptly. Otherwise, excessive unburned
fuel may reach the catalytic converter causing it to
overheat, which could start a fire.
Wa r n i n g !
As with any vehicle, do not idle, park or operate
this vehicle in areas where combustible materials
such as grass, hay or leaves can come into contact
with the hot exhaust system, as these materials
could be ignited and cause a vehicle fire.

245 Driving instructions
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Power assistance
BrakesThe condition of the parking brake system is checked
each time the vehicle is in the shop for the required
maintenance service.
If the parking brake is released and the brake warning
lamp in the instrument cluster stays on, the brake fluid
level in the reservoir is too low.
Brake pad wear or a leak in the system may be the
reason for low brake fluid in the reservoir.
Have the brake system inspected at an authorized
Mercedes-Benz Center immediately.
All checks and service work on the brake system should
be carried out by an authorized Mercedes-Benz Center.
Install only brake pads and brake fluid recommended by
Mercedes-Benz.
Wa r n i n g !
When the engine is not running, the brake and
steering systems are without power assistance.
Under these circumstances, a much greater effort is
necessary to stop or steer the vehicle.Wa r n i n g !
After driving in heavy rain for some time without
applying the brakes or through water deep enough
to wet brake components, the first braking action
may be somewhat reduced and increased pedal
pressure may be necessary to obtain expected
braking effect. Be sure to maintain a safe distance
from vehicles in front.Resting your foot on the brake pedal will cause
excessive and premature wear of the brake pads.It can also result in the brakes overheating thereby
significantly reducing their effectiveness. It may
not be possible to stop the vehicle in sufficient time
to avoid an accident.
Wa r n i n g !
If other than recommended brake pads are
installed, or other than recommended brake fluid
i s u sed , the brak in g properties of t he vehi c le c a n b e
degraded to an extent that safe braking is
substantially impaired. This could result in an
accident.

246 Driving instructions
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Caution!
When driving down long and steep grades, relieve the
load on the brakes by shifting into a lower gear to use
the engine’s braking power. This helps prevent
overheating of the brakes and reduces brake pad wear.
After hard braking, it is advisable to drive on for some
time, rather than immediately parking, so the air stream
will cool down the brakes faster.
Driving off
Apply the service brakes to test them briefly after
driving off. Perform this procedure only when the road
is clear of other traffic.
Warm up the engine smoothly. Do not place full load on
the engine until the operating temperature has been
reached.
When startin g of f on a s li ppe ry s urface, d o n ot allow on e
drive wheel to spin for an extended period with the ESP
switched off. Doing so may cause serious damage to the
drive train which is not covered by the Mercedes-Benz
Limited Warranty.Parking
Wa r n i n g !
To reduce the risk of personal injury as a result of
vehicle movement, before
turning off the engine
and leaving the vehicle always:
1. Keep right foot on service brake pedal.
2. Firmly depress parking brake pedal.
3. Move the selector lever to position “P”
(manual transmission: first or reverse gear).
4. Slowly release service brake pedal.
5. Turn front wheels towards the road curb.
6. Turn the electronic key to starter switch
position 0 and remove.
7. Take the electronic key and lock vehicle when
leaving.

276 Malfunction and warning messages
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
BATTERY / ALTERNATOR
* C = Category, see page 274
This message indicates a malfunction which must be
repaired immediately.
It may indicate that the poly-V-belt has broken. Should
this condition occur, the poly-V-belt must be replaced
before continuing to operate the vehicle. Otherwise, the
engine will overheat due to an inoperative water pump
which may result in damage to the engine.
Do not continue to drive the vehicle with this message
displayed.
Doing so could result in serious engine damage that is
not covered by the Mercedes-Benz Limited Warranty.
Line 1 Line 2 C*
BATTERY/ALTERNATOR VISIT WORKSHOP! 2

281 Malfunction and warning messages
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index COOLANT (coolant level)
* C = Category, see page 274When this message appears while driving, the coolant
level has dropped below the required level. If no leaks
are noticeable and the engine temperature does not
increase, continue to drive to the nearest service station
and have coolant added to the coolant system.The low engine coolant level warning should not be
ignored. Extended driving with the symbol displayed
may cause serious engine damage not covered by the
Mercedes-Benz Limited Warranty.
In cases of major or frequent minor coolant loss, have
the cooling system checked at your authorized
Mercedes-Benz Center as soon as possible.
Note:
Do not drive without coolant in the cooling system. The
engine will overheat causing major engine damage.
Monitor the coolant temperature gauge while driving,
see page 124.
See page 302 for instructions on topping up the coolant.Line 1 Line 2 C*
COOLANT CHECK LEVEL! 2
Wa r n i n g !
Do not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which may
burn if it comes into contact with hot engine parts.
You can be seriously burned.

282 Malfunction and warning messages
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
COOLANT (coolant temperature)
* C = Category, see page 274
1 This may indicate that the poly-V-belt has broken. Should this
con dition o ccur, the poly-V-belt must be repla ced befo re co ntin uin g
to operate the vehicle. Otherwise, the engine will overheat due to
an inoperative water pump which may result in damage to the
engine. Do not continue to drive the vehicle with this message
displayed. Doing so could result in serious engine damage that is
not covered by the Mercedes-Benz Limited Warranty.
2 The cooling fan for the coolant is faulty. Observe the coolant
temperature gauge. See page 124
During severe operating conditions and stop-and-go city
traffic, the coolant temperature may rise close to 120
°C.
The engine should not be operated with the coolant
temperature above 120
°C. Doing so may cause serious
engine damage which is not covered by the
Mercedes-Benz Limited Warranty.
Line 1 Line 2 C*
COOLANT STOP, ENGINE OFF!
1
1
COOLANT VISIT WORKSHOP!
2
2
Wa r n i n g !
Driving when your engine is badly overheated can
cause some fluids which may have leaked into the
engine compartment to catch fire. You could be
seriously burned.Steam from an overheated engine can cause serious
burns and can occur just by opening the engine
hood. Stay away from the engine if you see or hear
steam coming from it.Turn off the engine, get out of the vehicle and do
not stand near the vehicle until it cools down.

297 Engine compartment
Te ch n i c a l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hintsCar care Index Hood
Wa r n i n g !
To help prevent personal injury, stay clear of
moving parts when the hood is open and the engine
is running. Be sure the hood is properly closed
before driving. When closing hood, use extreme
caution not to catch hands or fingers.The radiator fan may continue to run for
approximately 30 seconds or even restart after the
engine has been turned off. Stay clear from fan
blades.If you see flames or smoke coming from the engine
compartment, or if the coolant temperature gauge
indicates that the engine is overheated, do not open
the hood. Move away from vehicle and do not open
the hood until the engine has cooled. If necessary,
call a fire department.
The engine is equipped with a transistorized
ignition system. Because of the high voltage it is
dangerous to touch any components (ignition coils,
spark plug sockets, diagnostic socket) of the
ignition system
• with the engine running,
• while starting the engine,
• if ignition is “on” and the engine is turned
manually.