engine overheat MERCEDES-BENZ SL-Class 2001 R129 Owner's Manual

78 Instrument cluster
Te ch n ica l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Coolant temperature gauge
During severe operating conditions and stop-and-go city
traffic, the coolant temperature may rise close to the red
marking.
The engine should not be operated with the coolant
temperature in the red zone. Doing so may cause
serious engine damage which is not covered by the
Mercedes-Benz Limited Warranty.Outside temperature indicator
The temperature sensor is located in the front bumper
area. Due to its location, the sensor can be affected by
road or engine heat during idling or slow driving. This
means that the accuracy of the displayed temperature
can only be verified by comparison to a thermometer
placed next to the sensor, not by comparison to external
displays (e.g. bank signs etc.).
Adaptation to ambient temperature takes place in steps
and depends on the prevailing driving conditions (stop-
and-go or moderate, constant driving) and amount of
temperature change.
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.
Wa r n i n g !
The outside temperature indicator is not designed
to serve as an Ice-Warning Device and is therefore
unsuitable for that purpose. Indicated
temperatures just above the freezing point do not
guarantee that the road surface is free of ice.

163 Catalytic converter
Te ch n ica 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.

177 Driving instructions
Te ch n ica 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 f luid 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
is used, the braking properties of the vehicle can be
degraded to an extent that safe braking is
substantially impaired. This could result in an
accident.The trunk is the preferred place to carry objects.

178 Driving instructions
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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 starting off on a slippery surface, do not allow one
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
Important!
Always engage the parking brake whenever parking or
leaving the vehicle. In addition, move selector lever to
position “P”.
When parking on hills, always set the parking brake.
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 the service brake pedal.
2. Firmly engage parking brake.
3. Move the selector lever to position “P”
4. Slowly release the service brake pedal.
5. Turn front wheels towards the road curb.
6. Turn the key to steering lock position 0 and
remove.
7. Take the key and lock vehicle when leaving.

209 Malfunction and indicator lamps
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index Low engine coolant level warning lamp
With the key in steering lock position 2, the
warning lamp comes on. It should go out
when the engine is running.
If the warning lamp does not go out after starting the
engine, or if it comes on while driving, then 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,
see page 225.
The low engine coolant level warning light should not be
ignored. Extended driving with the light illuminated
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.
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.

211 Malfunction and indicator lamps
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index Charge indicator lamp
Should the charge indicator lamp fail to
come on prior to starting when the key is in
steering l ock position 2 or sh ou ld it fa il to go
out after starting or during operation, this indicates a
malfunction which must be repaired immediately at an
authorized Mercedes-Benz Center.
If the charge indicator lamp comes on, or a loss of power
steering assistance is noticeable while the engine is
running, this may indicate that one of the two poly-V-
belts has broken. Should this condition occur, the poly-
V-belt must be replaced before continuing to operate the
vehicle. Otherwise, the engine may overheat due to an
inoperative water pump which may result in damage to
the engine.
Do not continue to drive the vehicle with the charge
indicator lamp illuminated. Doing so could result in
serious engine damage that is not covered by the
Mercedes-Benz Limited Warranty.Exterior lamp failure indicator lamp
With the key in steering lock position 2, an
indicator lamp comes on. It should go out
when the engine is running.
If the warning lamp does not go out after starting the
engine, or if it comes on while driving, this lamp
indicates a failure in the parking lamp, taillamp, stop
lamp, or low beam headlamp.
If a n exterior lamp fa ils, the indica tor lamp will com e on
only when that lamp is switched on.
If a brake lamp fails, the lamp failure indicator will
come on when applying the brake and stays on until the
engine is turned off.
Note:
If additional lighting equipment is installed (e.g.
auxiliary headlamps etc.) be certain to connect into the
fuse before the failure indicator monitoring unit in
order to avoid damaging the system.

221 Engine compartment
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hintsCar care Index To cl os e:
Lower hood and let it drop into lock from a height of
approx. 1 ft. (30 cm), assisting with hands placed flat on
edges of hood (3).
To avoid hood damage, please make sure that hood is
fully closed. If not, repeat closing procedure. Do not
push down on hood to attempt to fully close it.
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 another
approximate 30 seconds or even restart after the
engine has been turned off. Stay clear from fan
blades.
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.If you see flames, steam 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.

225 Coolant level
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hintsCar care Index Adding coolant
If coolant has to be added, a 50/50 mixture of water and
MB anticorrosion/antifreeze should be added.
Model SL 500
The drain plugs for the cooling system are located on
the right side of the engine block and at the bottom of
the radiator.
Model SL 600
The drain plugs for the cooling system are located on
the right and left sides of the engine block and at the
bottom of the radiator.
Anticorrosion/antifreeze, see coolants on page 281.
Wa r n i n g !
In order to avoid possible serious burns or injury:
• Use extreme caution when opening the hood if
there are any signs of steam or coolant leaking
from the cooling system, or if the coolant
temperature gauge indicates that the engine is
overheated.• Do not remove pressure cap on coolant
reservoir if engine temperature is above 194°F
(90°C). Allow engine to cool down before
removing cap. The coolant reservoir contains
hot fluid and is under pressure.• Using a rag, slowly open cap approximately 1/2
turn to relieve excess pressure. If opened
immediately, scalding hot fluid and steam will
be blown out under pressure.• Do not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which may
burn if it comes into contact with hot engine
parts.