engine MERCEDES-BENZ C320 2003 W203 Repair Manual

232 OperationDriving instructions
Coolant temperature
During severe operating conditions and
stop-and-go city traffic, the coolant tem-
perature may rise close to approx. 248°F
(120°C).
The engine should not be operated with
the coolant temperature over 248°F
(120°C). Doing so may cause serious en-
gine 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 uncon-
sciousness 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 win-
dow fully open at all times.
Warning!
G


Driving when your engine is badly over-
heated can cause some fluids, which
may have leaked into the engine com-
partment, to catch fire. You could be se-
riously burned.


Steam from an overheated engine can
cause serious burns and can occur just
by opening the engine hood. Stay away
f r o m t h e e n g i n e i f y o u s e e o r h e a r s t e a m
coming from it.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until it
cools down.

234 OperationAt the gas station
Check regularly and before a long trip
1Coolant level
More information on the coolant level
can be found in the “Operation” section
(
page 238).
2Brake fluid (fuse box cover removed)
More information on brake fluid can be
found in the “Technical data” section
(page 332).
Removing fuse box cover
(page 312).
3Windshield washer and headlamp
cleaning system*
For more information on refilling the
reservoir, see the “Operation” section
(page 241).Engine oil level
More information on engine oil can be
found in the “Operation” section
(
page 236).
Opening hood (
page 235).
Coolant
For normal replenishing, use water (pota-
ble water quality). More information on
coolant can be found in the “Operation”
section (
page 238).
Vehicle lighting
Check function and cleanliness. For more
information on replacing light bulbs, see
the “Practical hints” section (
page 290).
Exterior lamp switch (
page 101).
Tire inflation pressure
More information on tire inflation pressure
can be found in the “Operation” section
(
page 243).
iUse only 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 (MY 2003
Mercedes-Benz C 320 models, except
those equipped with manual transmis-
sion or 4MATIC*):
More information on Flexible Fuel Vehi-
cles can be found in the “Technical da-
ta” section (
page 334).
iLeaving the engine running and the fuel
cap open can cause the
?
lamp to
illuminate.
See also “Practical hints” section
(
page 259).

235 Operation
Engine compartment
Engine compartment
Hood
Opening
1Hood release
Pull lever1 downwards.
The hood is unlocked and handle2 will
extend out of the radiator grill. 2Handle for opening the hood

Pull handle2 to its stop out of radiator
grill.

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 vehi-
cle is in motion. Otherwise the hood could
be forced open by passing air flow.
!To avoid damage to the windshield wip-
ers 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 ap-
proximately 30 seconds or even restart af-
ter 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.

236 OperationEngine compartment
Closing
Let the hood drop from a height of ap-
proximately 1ft (30cm).
The hood will lock audibly.

Check to make sure that 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 high-
er engine speeds
Engine oil consumption checks should only
be made after the vehicle break-in period.
Checking engine oil level
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
Warning!
G
The engine is equipped with a transistorized
ignition system. Because of the high voltage
it is dangerous to touch any components (ig-
nition 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
Warning!
G
Be careful that you do not close the hood on
anyone.

237 Operation
Engine compartment
You can check the engine oil level on the
multifunction display.
Turn the key in the starter switch to
position2.
The standard display (
page 116) should
appear in the multifunction display.

Press button
k
or
j
, on the
steering wheel until the following mes-
sage is seen in the multifunction dis-
play:
ENGINE OIL LEVEL - MEASUREMENT IN
PROCESS! CORRECT MEASUREMENT ONLY
IF VEH. LEVEL
After about three seconds this mes-
sage is displayed: ENGINE OIL LEVEL – MEASURING NOWOne of the following messages will sub-
sequently appear in the indicator:

ENGINE OIL LEVEL – OK



ENGINE OIL LEVEL – ADD
1 QUART (1.0 LITER)!


ENGINE OIL LEVEL – ADD
1.5 QUARTS (1.5 LITERS)!


ENGINE OIL LEVEL – ADD
2 QUARTS (2.0 LITERS)!
Adding engine oil
1Filler neck
Unscrew the cap from filler neck1. Be
careful not to overfill with oil.
Be careful not to spill any oil when adding.
Avoid environmental damage caused by oil
entering the ground or water.

Screw the cap back on the filler neck.!Excessive 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.

238 OperationEngine compartmentOther display messages
If there is excessive engine oil with the en-
gine at normal operating temperature, the
following message will appear: ENGINE OIL LEVEL-REDUCE OIL LEVEL
Have excess oil siphoned.
If the key is not turned to position2 in the
starter switch:
FOR ENGINE OIL LEVEL IGNITION ON
PLEASE!
Switch on the ignition.
If you see the message:
OBSERVE WAITING PERIOD
Wait five minutes before repeating
check procedure.
If you see the message:
ENGINE OIL LEVEL-NOT WHEN ENGINE ON
!

Turn off the engine. If engine is at nor-
mal operating temperature, wait five
minutes before checking oil. If the en-
gine is not yet at normal operating tem-
perature, you must wait 30 minutes
before checking oil.If a proper oil level check cannot be per-
formed, the following message will appear:
MEASURING NOT POSSIBLE
Repeat the engine oil level check after
a short while.
See “Practical hints” (
page 270) if an en-
gine oil level indicator appears on the dis-
play when the engine is running.
More information on engine oil can be
found in the “Technical data” section
(
page 332).
Transmission fluid level
The transmission fluid level does not need
to be checked. If you notice transmission
fluid loss or gear shifting malfunctions,
have an authorized Mercedes-Benz Center
check the transmission.Coolant level
The engine coolant is a mixture of water
and anticorrosion/antifreeze. To check
the coolant level, the vehicle must be
parked on level ground and the engine
must be cool.
The coolant expansion tank is located on
the passenger side of the engine compart-
ment.

239 Operation
Engine compartment
1Coolant expansion tank
Using a rag, turn the cap slowly approx-
imately one half turn to the left to re-
lease any excess pressure.

Continue turning the cap to the left and
remove it.The coolant level is correct if the level


for cold coolant: reaches the black
top part of the reservoir


for warm coolant: is approx. 0.6 in
(1.5 cm) higher

Add coolant as required.

Replace and tighten cap.
More information on coolant can be found
in the “Technical data” section
(
page 336).
Warning!
G
In order to avoid any possibly serious burns:

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 indi-
cates that the coolant 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 the cap approx-
imately
1/2 turn to relieve excess pres-
sure. If opened immediately, scalding
hot fluid and steam will be blown out un-
der pressure.


Do not spill antifreeze on hot engine
parts. Antifreeze contains ethylene gly-
col which may burn if it comes into con-
tact with hot engine parts.

240 OperationEngine compartmentBattery
Your vehicle’s battery is located in the en-
gine compartment (
page 303).
The battery should always be sufficiently
charged in order to achieve its rated ser-
vice life.
If you use your vehicle mostly for short dis-
tance trips, you will need to have the bat-
tery charge checked more frequently.
When replacing the battery, always use
batteries approved by Mercedes-Benz.
If you do not intend to operate your vehicle
for an extended period of time, consult an
authorized Mercedes-Benz Center about
steps you need to observe.Batteries contain materials that can harm
the environment if disposed of improperly.
Recycling of batteries is the preferred
method of disposal. Many states require
sellers of batteries to accept old batteries
for recycling.
G
Observe all safety instructions
and precautions when handling
automotive batteries.
A
Risk of explosion
D
Keep flames or sparks away
from battery. Do not smoke.
B
Battery acid is caustic. Do not
allow it to come into contact
with skin, eyes or clothing.
In case it does, immediately
flush affected area with clear
water and seek medical help if
necessary.
E
Wear eye protection.
C
Keep children away.
F
Follow the instructions in this
Operator's Manual.

241 Operation
Engine compartment
Windshield washer system and headlamp cleaning* system
Fluid for the windshield washer system and
the headlamp cleaning system is supplied
from the windshield washer reservoir. It
has a capacity of

Vehicles without headlamp cleaning
system: approx. 3.2 US qt. (3.0 l).


Vehicles with headlamp cleaning
system*: approx. 6.4 US qt. (6.0 l).
During all seasons, add MB Windshield
Washer Concentrate “S” to water. Premix
the windshield washer fluid in a suitable
container.

Refill the reservoir with MB Windshield
Washer Concentrate and water (or
commercially available premixed wind-
shield washer solvent / antifreeze, de-
pending on ambient temperatures).Always use washer solvent/antifreeze
where temperatures may fall below
freezing. Failure to do so could result in
damage to the washer system/reser-
voir.
More information can be found in the
“Technical data” section (
page 338).1Washer fluid reservoir
Warning!
G
Washer solvent / antifreeze is highly flam-
mable. Do not spill washer solvent /
antifreeze on hot engine parts, because it
may ignite. You could be seriously burned.
!Only use washer fluid which is suitable
for plastic lenses. Improper washer flu-
id can damage the plastic lenses of the
headlamps.

245 Operation
Winter driving
Winter driving
Before the onset of winter have your vehi-
cle winterized at an authorized
Mercedes-Benz Center. This service in-
cludes:

Check of anticorrosion and antifreeze
concentration.


Addition of cleaning concentrate to the
water of the windshield and headlamp
cleaning system. Add MB Concentrate
“S” to a premixed windshield washer
solvent / antifreeze which is formulated
for below freezing temperatures
(page 338).


Battery test. Battery capacity drops
with decreasing ambient temperature.
A well charged battery helps to ensure
that the engine can be started, even at
low ambient temperatures.


Tire change. We recommend M+S rat-
ed radial-ply tires on all four wheels for
the winter season.
Winter tires
Always use winter tires at temperatures
below 39°F (4°C) and whenever wintry
road conditions prevail. Use of winter tires
is the only way to achieve the maximum ef-
fectiveness of ABS, ESP and 4MATIC* in
winter operation.
For safe handling, ensure that all mounted
winter tires are of the same make and have
the same tread design.Always observe the speed rating of the
winter tires installed on your vehicle. If the
maximum speed for which your tires are
rated is below the speed rating of your ve-
hicle, you must place a notice to this effect
where it will be seen by the driver. Such no-
tices are available from your tire dealer or
from any authorized Mercedes-Benz Cen-
ter.Warning!
G
Winter tires with a tread depth under 0.16 in
(4 mm) must be replaced. They are no long-
er suitable for winter operation.
Warning!
G
If you use your spare tire when winter tires
are fitted on the other wheels, be aware that
the difference in tire characteristics may
very well impair turning stability and that
overall driving stability may be reduced.
Adapt your driving style accordingly.
Have the spare tire replaced with a winter
tire at the nearest authorized
Mercedes-Benz Center.