2005 MERCEDES-BENZ C320 check engine

181 Controls in detail
Climate control
Air conditioning
The air conditioning is operational while
the engine is running and cools the interior
air to the temperature set by the operator.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 175).
The indicator lamp on the button
comes on.
The cooling function switches off after
a short delay.Activating
Moist air can fog up the windows. You can
dehumidify the air with the air condition-
ing.

Press button± (
page 175).
The indicator lamp on the button goes
out.
The air conditioning uses the
refrigerant R134a. This refrigerant is free
of CFCs which are harmful to the ozone
layer.
iCondensation may drip out from under-
neath the vehicle. This is normal and
not an indication of a malfunction.Warning!
G
If you turn off the cooling function, the
vehicle will not be cooled when weather
conditions are warm. The windows can fog
up more quickly. Window fogging may
impair visibility and endanger you and
others.
!If the air conditioning cannot be turned
on again, this indicates that the air
conditioning is losing refrigerant. The
compressor has turned itself off.
Have the air conditioning checked at
the nearest authorized Mercedes-Benz
Center.

277 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 283) and see
“Fuels, coolants, lubricants, etc.”
(
page 387).
Brake fluid
Removing fuse box cover (
page 370).Windshield washer and headlamp
cleaning system*
For more information on filling up the
washer reservoir, see “Windshield washer
system and headlamp cleaning system*”
(
page 285).
Engine oil level
For more information on engine oil level,
see “Engine oil” (
page 279).
Vehicle lighting
Check function and cleanliness. For more
information on replacing light bulbs, see
“Replacing bulbs” (page 344).
Exterior lamp switch (page 109).
Tire inflation pressure
More information on tire inflation pressure
(
page 287).
iOpening the hood, see (
page 278).
!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 303).

279 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
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
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.

280 OperationEngine compartmentChecking engine oil level with the
control system
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
stationary for at least five 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
To check the engine oil level via the
multifunction display, do the following:

Switch on ignition (
page 33).
The standard display (
page 121) should
appear in the multifunction display.

Press buttonk orj on the
steering wheel until the following
message is seen in the multifunction
display:One of the following messages will
subsequently appear in the indicator:


Engine oil level
OK


Add 1.0 qt engine oil
for max. oil level(Canada:
1.0 l
)


Add 1.5 qts engine oil
for max. oil level(Canada:
1.5 l
)


Add 2.0 qts engine oil
for max. oil level(Canada:
2.0 l
)

If necessary, add engine oil.
For adding engine oil see (
page 281).
More information on engine oil can be
found in the “Technical data” section
(
page 387) and (
page 390).
Other display messages
If the SmartKey is not turned to position2
in the starter switch, the following
message will appear:
Switch ignition on to
check engine oil level
Switch on ignition (
page 33).
iIf you want to interrupt the checking
procedure, press thek orj
button on the multifunction steering
wheel.

281 Operation
Engine compartment
If you see the message:Observe waiting time
If engine is at operating temperature,
wait five minutes before repeating
check procedure.

If engine is not at operating tempera-
ture yet, 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 operating tempera-
ture, wait five minutes before checking
oil.

If the engine is not at operating temper-
ature yet, you must wait 30 minutes
before checking oil.If there is excess engine oil with the engine
at operating temperature, the following
message will appear:
Engine oil level
Reduce oil level
Have excess oil siphoned or drained
off. Contact an authorized
Mercedes-Benz Center.
More information on messages in the
display concerning engine oil can be found
in the “Practical hints” section
(
page 320) and (
page 321).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 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 damage
not covered by the Mercedes-Benz
Limited Warranty.

282 OperationEngine compartmentC 230 Kompressor (all models)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.
C 240 (all models), C 320 (all models),
C55AMG1Filler 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.
More information on engine oil can be
found in the “Technical data” section
(
page 387) and (
page 390).
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.
!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.
!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.

283 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
2Cap

Using a rag, turn cap2 slowly approx-
imately one half turn to the left to
release 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.
For more information on coolant, see
“Coolants” (
page 394).
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 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
approximately
1/2 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.

284 OperationEngine compartmentBattery
Your vehicle’s battery is located in the
engine compartment on the right hand
side (
page 360).
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.
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.