2004 MERCEDES-BENZ C320 COUPE check engine

156 Controls in detailClimate controlAir conditioning
The air conditioning is operational while
the engine is running and cools the interior
air to the temperature set by the operator.Activating
Moist air can fog up the windows. You can
dehumidify the air with the air condition-
ing.

Press± again (
page 151).
The indicator lamp on the button±
goes out.
The air conditioning system uses the refrig-
erant R134a. This refrigerant is free of
CFCs which are harmful to the ozone layer.
Deactivating
It is possible to deactivate the air condi-
tioning (cooling) function of the climate
control system. The air in the vehicle will
then no longer be cooled or dehumidified.

Press button± (
page 151).
The indicator lamp on the button±
comes on.
iCondensation may drip out from under-
neath the vehicle. This is normal and
not an indication of a malfunction.
!If the air conditioning cannot be turned
on again, this indicates that the air con-
ditioning system is losing refrigerant.
The compressor has turned itself off.
Have the air conditioning system
checked at the nearest authorized
Mercedes-Benz Center.

234 OperationAt the gas station
Check regularly and before a long trip
1Coolant level
For more information, see “Coolant lev-
el” (
page 241).
2Brake fluid (fuse box cover removed)
Removing fuse box cover, see “Fuses”
(
page 317).
3Windshield washer and headlamp
cleaning system*
For more information on filling up the
washer reservoir, see “Windshield
washer system and headlamp cleaning
system” (
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 are identified by
a label reading Premium gasoline or
E85 only! on the fuel filler flap.
For more information,see “Flexible Fuel
Vehicles” (
page 334).
iLeaving the engine running and the fuel
cap open can cause the ? lamp to
illuminate.
For more information , see“Practical
hints” section (
page 260).


235 Operation
At the gas station
Engine oil level
For more information on engine oil, see
“Engine oil” (
page 237).
Opening hood, see (
page 236).
Coolant
For normal replenishing, use water (pota-
ble water quality). For more information on
coolant, see “Coolant level” (
page 241)Vehicle lighting
Check function and cleanliness. For infor-
mation on replacing light bulbs, see “Re-
placing bulbs” (
page 293).
Exterior lamp switch (
page 98).
Tire inflation pressure
For information on tire inflation pressure,
see “Checking tire inflation pressure”
(
page 245).
!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. Noti-
fy 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 259).

237 Operation
Engine compartment
Closing
Let the hood drop from a height of ap-
proximately 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
If you see flames or smoke coming from the
engine compartment, or if the coolant tem-
perature display 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
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.

238 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 109) 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 239).
For more information on engine oil, see
“Technical data” section (
page 330).
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.

239 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.
For more information on messages in the
display concerning engine oil, see “Practi-
cal hints” (
page 275).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 port-
folio.
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 Prod-
ucts pamphlet that meets the specifi-
cation indicated on the oil filler cap.
Using engine oils of other specification
may cause the FSS to incorrectly deter-
mine the next service interval and will
r e s u l t i n e n g i n e d a m a g e n o t c o v e r e d b y
the Mercedes-Benz Limited Warranty.

241 Operation
Engine compartment
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.
For more information on coolant, see
“Coolants” (
page 336).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.
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 display in-
dicates 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 ½ 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 ignite and burn if it comes
into contact with hot engine parts.

242 OperationEngine compartmentBattery
Your vehicle’s battery is located in the en-
gine compartment on the right hand side.
The battery should always be sufficiently
charged in order to achieve its rated ser-
vice life. Refer to Service Booklet for bat-
tery maintenance intervals.
If you use your vehicle mostly for
short-distance trips, you will need to have
the battery charge checked more frequent-
ly.
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.