MERCEDES-BENZ C350 4MATIC 2007 W203 Owner's Manual

270 Operation
Driving instructions
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
Maintenance Booklet.
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 (CO), and inhaling it can cause
unconsciousness and possible 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.

271 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.
1To open the fuel filler flap
2To insert the fuel filler cap
3Supplemental tire inflation pressure in-
formation
Warning!G
Gasoline is highly flammable and poisonous.
It burns violently and can cause serious per-
sonal injury.
Never allow sparks, flame or smoking mate-
rials near gasoline!
Turn off the engine before refueling
Whenever you are around gasoline, avoid in-
haling fumes and skin or clothing contact,
extinguish all smoking materials.
Direct skin contact with fuels and the inha-
lation of fuel vapors can damage to your
health.
Warning!G
C 230/C 230 Sport:
Flexible Fuel Vehicles (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 refueling. Never
smoke or create sparks close to ethanol.
iIn case that the central locking system does
not release the fuel filler flap, or the opening
mechanism is clamping, notify Roadside Assis-
tance or an authorized Mercedes-Benz Center.

272 Operation
At the gas station
Turn the engine off by turning the
SmartKey to position0.
Remove the SmartKey from the starter
switch.
Open the fuel filler flap by pushing at
the point indicated by arrow1.
The fuel filler flap springs open.
Turn fuel cap counterclockwise and
hold on to it until possible pressure is
released.
Take off cap and set it in direction of
arrow2 in the recess on the 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 clockwise
until it audibly engages.
Close fuel filler flap.
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.
C 230/C 230 Sport:
Flexible Fuel Vehicles are identified by a label
reading Premium gasoline or E85 only! on the
fuel filler flap.
For more information on gasoline or E85, see
“Premium unleaded gasoline” (
page 413) or
the Factory Approved Service Products pam-
phlet.
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.
iMake sure to close the fuel filler flap before
locking your vehicle as the flap locking pin
prevents closing after you have locked the
vehicle.
iLeaving the engine running and the fuel cap
open can cause the yellow fuel tank reserve
warning lamp to flash and theú malfunction
indicator lamp (USA only) or the± malfunc-
tion indicator lamp (Canada only) to illuminate.
For more information, see “Practical hints”
(
page 325) and (page 326).

273 Operation
At the gas station
Check regularly and before a long trip
1Coolant
2Brake fluid (fuse box cover removed)
3Windshield washer and headlamp
cleaning system*Coolant
For normal replenishing, use water (pota-
ble water quality). For more information,
see “Coolant level” (
page 278) and see
“Fuels, coolants, lubricants, etc.”
(
page 409).
Brake fluid
Removing fuse box cover (
page 392).Windshield washer and headlamp
cleaning system*
For more information on filling up the
washer reservoir, see “Windshield washer
system and headlamp cleaning system*”
(
page 280).
Engine oil level
For more information on engine oil level,
see “Engine oil” (
page 276).
Vehicle lighting
Check function and cleanliness. For more
information on replacing light bulbs, see
“Replacing bulbs” (
page 367).
Exterior lamp switch (
page 109).
Tire inflation pressure
More information on tire inflation pressure
(
page 290).
iOpening the hood, see (page 274).
!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 324).

274 Operation
Engine compartment
Hood
Opening
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.
This could cause the hood to come loose
and injure you and/or others.
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.
Warning!G
You could be injured when the hood is open
- even when the engine is turned off.
Parts of the engine can become very hot. To
prevent burns, only touch owner serviceable
components described in the Operator’s
Manual and comply with all relevant safety
precautions.
Warning!G
To help prevent personal injury, stay clear of
moving parts when the hood is open and the
engine is running.
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
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

275 Operation
Engine compartment
The hood lock release lever is located to
the left of the steering wheel under the
dashboard.
1Hood lock release lever
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. Closing
Let the hood drop from a height of
approximately 1 ft (30 cm).
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.
!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
When closing the hood, use extreme caution
not to catch hands or fingers.
Be careful that you do not close the hood on
anyone.
Make sure that the hood is securely en-
gaged before driving off. Do not continue
driving if the hood can no longer engage af-
ter an accident, for example. The hood could
otherwise come loose while the vehicle is in
motion and injure you and/or others.

276 Operation
Engine compartment
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.
Checking engine oil level
When checking the oil level

the vehicle must be parked on level
ground

with the engine at operating tempera-
ture, the vehicle must have been sta-
tionary for at least 5 minutes with the
engine turned off

with the engine not at operating tem-
perature yet, the vehicle must have
been stationary for at least 30 minutes
with the engine turned off
1Oil dipstick
2Upper (max) mark
3Lower (min) mark
To check the engine oil level with the oil
dipstick, do the following:
Open the hood (page 274).
Pull out oil dipstick1.
Wipe oil dipstick1 clean.
Fully insert oil dipstick1 into the
dipstick guide tube.
Pull out oil dipstick1 again after
approximately 3 seconds to obtain ac-
curate reading.
The oil level is correct when it is be-
tween the lower (min) mark3 and
upper (max) mark2 of oil dipstick1.
If necessary, add engine oil.
For adding engine oil, see “Adding en-
gine oil” (
page 277).
For more information on engine oil, see
“Fuels, coolants, lubricants, etc.”
(
page 409).
iDo not use any special lubricant additives,
as these may damage the drive assemblies. Us-
ing special additives not approved by
Mercedes-Benz may cause damage not covered
by the Mercedes-Benz Limited Warranty. More
information on this subject is available at any
Mercedes-Benz Center.iThe filling quantity between the upper and
lower marks on the oil dipstick is approximately
2.1 US qt. (2.0 l).

277 Operation
Engine compartment
For more information on messages in the
multifunction display concerning engine
oil, see the “Practical hints” section
(
page 348).
Adding engine oil
1Filler cap
Unscrew filler cap1 from filler neck.
Add engine oil as required. 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 filler cap1 back on filler neck.
For more information on engine oil, see the
“Technical data” section (
page 409) and
(
page 412).
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.
!Only use approved engine oils and oil filters
required for vehicles with Maintenance System
(U.S. vehicles) or FSS (Canada vehicles). For a
listing of approved engine oils and oil filters,
refer to the Factory Approved Service Products
pamphlet in your vehicle literature portfolio, or
contact an authorized Mercedes-Benz Center.
Using engine oils and oil filters of specification
other than those expressly required for the
Maintenance System (U.S. vehicles) or FSS
(Canada vehicles), or changing of oil and oil filter
at change intervals longer than those called for
by the Maintenance System (U.S. vehicles) or
FSS (Canada Vehicles) will result in engine or
emission control system damage not covered by
the Mercedes-Benz Limited Warranty.
!Excess oil must be siphoned or drained off.
It could cause damage to the engine and emis-
sion control system not covered by the
Mercedes-Benz Limited Warranty.

278 Operation
Engine compartment
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.
1Coolant expansion tank
2CapUsing a rag, turn cap2 slowly approx-
imately one half turn counterclockwise
to release any excess pressure.
Continue turning the cap counterclock-
wise 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.
For more information on coolant, see
“Coolants” (
page 416).
Warning!G
In order to avoid any potentially 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 coolant temperature is
above 158°F (70°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
approximately1/2 turn to relieve excess
pressure. If opened immediately, scald-
ing 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.

279 Operation
Engine compartment
Battery
Your vehicle’s battery is located in the
engine compartment on the right hand
side (
page 383).
The battery should always be sufficiently
charged in order to achieve its rated
service life. Refer to Maintenance Booklet
for battery maintenance intervals.
If you use your vehicle mostly for
short-distance trips, you will need to have
the battery 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.
Warning!G
Observe all safety instructions and precau-
tions when handling automotive batteries.
Risk of explosion.
Fire, open flames and smoking
are prohibited when handling
batteries. Avoid creating sparks.
Battery acid is caustic. Do not
allow it to come into contact
with skin, eyes or clothing.
Wear suitable protective cloth-
ing, especially gloves, apron and
faceguard.
Wear eye protection.
Rinse any acid spills immediate-
ly with clear water. Contact a
physician if necessary.
Keep children away.
Follow the instructions in this
Operator’s Manual.