engine MERCEDES-BENZ C320 2004 W203 Repair Manual

246 OperationDriving instructionsPassenger compartmentDriving abroad
Abroad, there is an extensive
Mercedes-Benz service network at your
disposal. If you plan to drive into areas
which are not listed in the index of your
Mercedes-Benz Center directory, you
should request pertinent information from
your authorized Mercedes-Benz Center.Control and operation of radio
transmitters
COMAND*, radio and telephone*Telephones* and two-way radios
Radio transmitters, such as a portable
telephone or a citizens band unit should
only be used inside the vehicle if they are
connected to an antenna that is installed
on the outside of the vehicle.
Refer to the radio transmitter operation
instructions regarding use of an external
antenna.
Warning!
G
Always fasten items being carried as
securely as possible.
In an accident, during hard braking or sud-
den maneuvers, loose items will be thrown
around inside the vehicle, and cause injury
to vehicle occupants unless the items are
securely fastened in the vehicle.
The trunk is the preferred place to carry
objects.
Warning!
G
Please do not forget that your primary
responsibility is to drive the vehicle safely.
Only operate the COMAND (Cockpit
Management and Data System), radio or
telephone
1 if road, weather and traffic
conditions permit.
Bear in mind that at a speed of just 30 mph
(approximately 50 km/h), your vehicle is
covering a distance of approximately
44 feet (approximately 13.5 m) every
second.
1Observe all legal requirements
Warning!
G
Never operate radio transmitters equipped
with a built-in or attached antenna (i.e. with-
out being connected to an external antenna)
from inside the vehicle while the engine is
running. Doing so could lead to a malfunc-
tion of the vehicle’s electronic system,
possibly resulting in an accident and
personal injury.

247 Operation
Driving instructions
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.
Emission control
Certain systems of the engine serve to
keep the toxic components of the exhaust
gases within permissible limits required by
law.
These systems, of course, will function
properly only when maintained strictly
according to factory specifications. Any
adjustments on the engine should,
therefore, be carried out only by qualified
Mercedes-Benz Center authorized techni-
cians. Engine adjustments should not be
altered in any way. Moreover, the specified
service jobs must be carried out regularly
according to Mercedes-Benz servicing
requirements. For details refer to the
Service Booklet.
!To prevent damage to the catalytic
converters, only use 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 and start a fire.
Warning!
G
As with any vehicle, do not idle, park or
operate this vehicle in areas where combus-
tible 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.

248 OperationDriving instructions
Coolant temperature
During severe operating conditions and
stop-and-go city traffic, the coolant
temperature may rise close to
approximately 248°F (120°C).
The engine should not be operated with
the coolant temperature over 248°F
(120°C). Doing so may cause serious
engine damage which is not covered by the
Mercedes-Benz Limited Warranty.
Warning!
G
Inhalation of exhaust gas is hazardous to
your health. All exhaust gas contains carbon
monoxide, and inhaling it can cause
unconsciousness and lead to death.
Do not run the engine in confined areas
(such as a garage) which are not properly
ventilated. If you think that exhaust gas
fumes are entering the vehicle while driving,
have the cause determined and corrected
immediately. If you must drive under these
conditions, drive only with at least one
window fully open at all times.
Warning!
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 hood. Stay away from
the engine if you see or hear steam com-
ing from it.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until the
engine has cooled down.

249 Operation
At the gas station
At the gas station
RefuelingThe fuel filler flap is located on the
right-hand side of the vehicle towards the
rear. Locking/unlocking the vehicle with
the SmartKey automatically locks/unlocks
the fuel filler flap.

Turn the engine off by turning the
SmartKey to position0.

Remove the SmartKey from the starter
switch.
Warning!
G
Gasoline is highly flammable and poisonous.
It burns violently and can cause serious
injury. Whenever you are around gasoline,
avoid inhaling fumes and skin contact,
extinguish all smoking materials. Never
allow sparks, flame or smoking materials
near gasoline!
Warning!
G
Flexible Fuel Vehicles only (identified by a
label reading Premium gasoline or E85
only! on fuel filler flap):
Ethanol fuel (E85) and its vapors are highly
flammable, poisonous and burn easily. Etha-
nol fuel can cause serious injuries if ignited
or if you come into contact with it or inhale
fumes of it. Avoid inhalation of Ethanol
fumes and skin contact with Ethanol. Extin-
guish all open flames before fueling. Never
smoke or create sparks close to Ethanol.


250 OperationAt the gas station
Open fuel filler flap by pushing at the
point indicated by the arrow.
The fuel filler flap springs open.

Turn fuel cap to the left and hold on to
it until possible pressure is released.

Take off cap and set it in the recess on
fuel filler flap.
To prevent fuel vapors from escaping
into open air, fully insert filler nozzle
unit.

Only fill your tank until the filler nozzle
unit cuts out – do not top up or overfill.

Replace fuel cap by turning it to the
right.
You will hear when fuel cap is
tightened.

Close fuel filler flap.Warning!
G
Overfilling of the fuel tank may create
pressure in the system which could cause a
gas discharge. This could cause the gas to
spray back out when removing the fuel
pump nozzle, which could cause personal
injury.
iOnly use premium unleaded gasoline
with a minimum Posted Octane Rating
of 91 (average of 96 RON/86 MON).
Information on gasoline quality can
normally be found on the fuel pump.
More information on gasoline can be
found in the Factory Approved Service
Products pamphlet.
Flexible Fuel Vehicles are identified by
a label reading Premium gasoline or
E85 only! on fuel filler flap.
For more information, see “Flexible
Fuel Vehicles” (
page 354).
iLeaving the engine running and the fuel
cap open can cause the? malfunc-
tion indicator lamp to illuminate.
For more information, see “Practical
hints” (
page 276).


251 Operation
At the gas station
Check regularly and before a long trip
1Coolant level
For more information on coolant, see
“Coolant level” (
page 257).
2Brake fluid (fuse box cover removed)
Removing fuse box cover
(
page 333).
3Windshield washer and headlamp
cleaning system*
For more information on filling up the
washer reservoir, see “Windshield
washer system and headlamp cleaning
system*” (
page 259).Engine oil level
For more information on engine oil level,
see “Engine oil” (
page 253).
Opening hood (
page 252).
Vehicle lighting
Check function and cleanliness. For more
information on replacing light bulbs, see
“Replacing bulbs” (page 310).
Exterior lamp switch (page 102).
Tire inflation pressure
More information on tire inflation pressure
(
page 261).
!If you find that the brake fluid in the
brake fluid reservoir has fallen to the
minimum mark or below, have the
brake system checked for brake pad
thickness and leaks immediately.
Notify an authorized Mercedes-Benz
Center immediately. Do not add brake
fluid as this will not solve the problem.
For more information, see “Practical
hints” (
page 275).

252 OperationEngine compartment
Engine compartmentHood
Opening
1Hood release
Pull lever1 downwards.
The hood is unlocked and handle2
will extend out of the radiator grille. 2Handle for opening the hood

Pull handle2 to its stop out of
radiator grille.

Pull up on the hood (do not pull up on
the handle) and then release it.
The hood will be automatically held
open at shoulder height by gas-filled
struts.
Warning!
G
Do not pull the release lever while the
vehicle is in motion. Otherwise the hood
could be forced open by passing air flow.
!To avoid damage to the windshield
wipers or hood, never open the hood if
the wiper arms are folded forward away
from the windshield.
Warning!
G
To help prevent personal injury, stay clear of
moving parts when the hood is open and the
engine is running. Make sure the hood is
properly closed before driving. When closing
the 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 of fan blades.Warning!
G
If you see flames or smoke coming from the
engine compartment, or if the coolant tem-
perature 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 the fire department.

253 Operation
Engine compartment
Closing
Let the hood drop from a height of
approximately 1ft (30cm).
The hood will lock audibly.

Check to make sure the hood is fully
closed.
If you can raise the hood at a point
above the headlamps, then it is not
properly closed. Open it again and let it
drop with somewhat greater force.
Engine oil
The amount of oil your engine needs will
depend on a number of factors, including
driving style. Higher oil consumption can
occur when

the vehicle is new


the vehicle is driven frequently at
higher engine speeds
Engine oil consumption checks should only
be made after the vehicle break-in period.
Warning!
G
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, diagnos-
tic socket) of the ignition system

with the engine running


while starting the engine


if ignition is “on” and the engine is
turned manually
Warning!
G
Be careful that you do not close the hood on
anyone.
iDo not use any special lubricant addi-
tives, as these may damage the drive
assemblies. Using special additives not
approved by Mercedes-Benz will
restrict your warranty entitlement.
More information on this subject is
available at any Mercedes-Benz
Center.

254 OperationEngine compartmentChecking engine oil level with the
control system
When checking the oil level the vehicle
must

be parked on level ground


be at normal operating temperature


have been stationary for at least five
minutes with the engine turned off
To check the engine oil level via the
multifunction display, do the following:

Turn the SmartKey in the starter switch
to position2.
The standard display (
page 113) should
appear in the multifunction display.

Press buttonk orj on the
steering wheel until the following
message is seen in the multifunction
display:ENGINE OIL LEVEL
MEASURING NOW
MEASURE. CORRECT
ONLY IF VEH. LEVEL
One of the following messages will
subsequently appear in the indicator:

ENGINE OIL LEVEL
OK


ADD 1.0 Qt. TO
REACH MAX. OIL LEVEL!(Canada:
1.0 LITER
)


ADD 1.5 Qts. TO
REACH MAX. OIL LEVEL!(Canada:
1.5 LITERS
)


ADD 2.0 Qts. TO
REACH MAX. OIL LEVEL!(Canada:
2.0 LITERS
)

If necessary, add engine oil.
For adding engine oil see (
page 255).
More information on engine oil can be
found in the “Technical data” section
(
page 349) and (
page 352).
Other display messages
If the SmartKey is not turned to position2
in the starter switch, the following
message will appear:
FOR ENGINE OIL LEVEL
SWITCH ON IGNITION!
Switch on the ignition.iIf you want to interrupt the checking
procedure, press thek orj
button on the multifunction steering
wheel.

255 Operation
Engine compartment
If you see the message:OBSERVE WAITING PERIOD
If engine is at normal operating
temperature, wait five minutes before
repeating check procedure.

If engine is not yet at normal operating
temperature, wait 30 minutes before
repeating check procedure.
If you see the message:
ENGINE OIL LEVEL
NOT WHEN ENGINE ON!
Turn off the engine.

If the engine is at normal operating
temperature, wait five minutes before
checking oil.

If the engine is not yet at normal
operating temperature, you must wait
30 minutes before checking oil.If there is excess engine oil with the engine
at normal operating temperature, the
following message will appear:
ENGINE OIL LEVEL
REDUCE OIL LEVEL
Have excess oil siphoned or drained
off. Contact your authorized
Mercedes-Benz Center.
More information on messages in the
display concerning engine oil can be found
in the “Practical hints” section
(
page 291). Adding engine oil!Excess oil must be siphoned or drained
off. It could cause damage to the
engine and catalytic converter not
covered by the Mercedes-Benz Limited
Warranty.
!Only use approved engine oils. For a
listing of approved engine oils, refer to
the Factory Approved Service Products
pamphlet in your vehicle literature
portfolio.
In addition, check the oil filler cap for
important information pertaining to the
engine oil needing to meet a specific
Mercedes-Benz specification
(e.g. MB 229.5). If such information is
printed on the oil filler cap, only use an
engine oil from the list of approved
engine oils in the Factory Approved
Service Products pamphlet that meets
the specification indicated on the oil
filler cap. Using engine oils of other
specification may cause the FSS to
incorrectly determine the next service
interval and will result in engine dam-
age not covered by the Mercedes-Benz
Limited Warranty.