2008 AUDI A4 coolant level

Instruments and warning/indicator lamps 12Warning symbol in instrument cluster

If the symbol
 lights up in the display, this means that either the
coolant temperature is too high or the coolant level is too low
⇒page 33.
If the needle is at the top end of the dial, this means the coolant
temperature is too high. Stop the vehicle, switch off the engine and
wait for it to cool down. If the warning lamp starts flashing again
after just a short distance, contact a qualified workshop.
WARNING
•
Before opening the bonnet and checking the coolant level,
please observe the warning information on ⇒page 255, “Working
on components in the engine compartment”.
•
Never open the bonnet if you can see or hear steam or coolant
escaping from the engine compartment; there is a risk of being
scalded. Wait until you can no longer see or hear escaping steam
or coolant.Caution
•
Additional lights and other accessories in front of the air inlet
reduce the cooling effect of the radiator. At high outside tempera-
tures and high engine loads, there is a risk of the engine over-
heating.
•
The front spoiler also ensures proper distribution of the cooling
air when the vehicle is moving. If the spoiler is damaged this can
reduce the cooling effect, which could cause the engine to overheat.
You should obtain professional assistance.
Rev counter
The rev counter indicates the number of engine revolu-
tions per minute.You should select a lower gear if the engine speed drops below
1500 rpm. The start of the red zone on the dial indicates the
maximum engine speed which may be used briefly when the engine
is warm and after it has been run in properly. However, it is advisable
to change up a gear or move the selector lever to “D” (or lift your
foot off the accelerator) before the needle reaches the red zone.
Caution
Never allow the rev counter needle ⇒page 11, fig. 2 to go into
the red zone on the dial for more than a very brief period: there is a
risk of damaging the engine. The start of the red zone on the dial is
different for some engine versions.
For the sake of the environment
Changing up a gear early will help you to save fuel and minimise
engine noise.
button
This button has a number of different functions.
A2
SET
Fig. 3 Instrument
cluster: SET button
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Driver information system31
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data For example, in the event of an oil pressure malfunction the oil pres-
sure symbol

will appear in the display. In addition, the following
message will appear:
Switch off engine and check oil level
The message will disappear from the display after about 5 seconds.
If required, the message can be called up again by briefly pressing
the button ⇒page 30, fig. 24.
Driver messages and yellow symbols
If a yellow warning symbol appears in the display, it will automati-
cally be accompanied by the corresponding driver message.
For example, if the symbol
 appears (windscreen washer fluid
low), the display will also show the message:
Please top up washer fluid
The message will disappear after a few seconds. If required, the
message can be called up again by briefly pressing the
button.
Red symbols
A red symbol warns of a serious malfunction.–Stop the vehicle.– Switch off the engine.
– Check the function displayed. Obtain professional assist-
ance if necessary.
The red symbols indicate a Priority 1 fault (serious malfunction).
Should a Priority 1 fault occur, a red warning symbol will appear at
the top of the display ⇒fig. 25. The symbol is accompanied by a
driver message giving you more information about the fault. This
symbol is accompanied by three warning chimes. The symbol will
keep flashing until the fault is corrected.
If several Priority 1 faults are detected at the same time, the symbols
are displayed one after the other for about 2 seconds at a time.
This message will disappear after about 5 seconds, but you can call
it up again at any time by pressing the button ⇒page 30.
SET
SET
Fig. 25 Display:
Symbol for serious
malfunction

Alternator fault
⇒page 32

Fault in brake system/parking
brake
⇒page 32

Coolant level too low / coolant
temperature too high
⇒page 33

Engine oil pressure too low
⇒page 33

Add engine oil immediately
⇒page 34

Fault in the steering system
⇒page 34

Ignition lock defective
⇒page 34

Tyre pressure monitoring
⇒page 39
SET
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Driver information system 32Alternator fault

If the symbol
 flashes in the instrument cluster display, there is an
alternator fault or a fault in the vehicle's electrical system. In addi-
tion, a message will appear. This message will disappear after about
5 seconds, but you can call it up again at any time by pressing the
button.
You should normally be able to drive to the next available qualified
workshop. However, you should avoid using electrical equipment
that is not absolutely necessary because this will drain the battery.
Caution
If the coolant warning lamp
 in the instrument display lights up
as well as the alternator warning lamp while driving ⇒page 33, stop
the vehicle immediately and switch off the engine. In this case the
coolant pump is no longer being driven, and there is a risk of engine
damage.
Fault in the brake system

A fault in the brake system should be corrected as soon as
possible.If the symbol

flashes in the display, there is a fault in the
brake system. The symbol is accompanied by a driver
message giving you more information about the fault. This
message will disappear after about 5 seconds, but you can
call it up again at any time by pressing the button:
Stop vehicle and check brake fluid level
– Stop the vehicle.
– Check the brake fluid level ⇒page 262.
– Obtain professional assistance if necessary.Warning! Fault in ABS brake system. Contact
workshop
– Drive carefully to the nearest qualified workshop and
have the fault rectified ⇒.
Parking brake ! Please contact workshop
– If the symbol appears after you switch on the ignition
when the vehicle is stationary, please check whether you
can release the parking brake. If this is possible, you
should drive without delay to the nearest qualified work-
shop and have the fault rectified. If the parking brake
cannot be released you should obtain professional
assistance.
– If this symbol should appear while driving, there may be
a malfunction in the drive-away assist or the emergency
brake functions. You may not be able to apply the parking
brake. It is also possible that you cannot release the
parking brake after it has been applied. Drive the vehicle
to a qualified workshop and have the fault repaired.
If the ABS fails, the ABS warning lamp
 will light up together with
the brake warning symbol
 ⇒.
WARNING
•
Before opening the bonnet and checking the brake fluid level,
observe the warning information on ⇒page 255, “Working on
components in the engine compartment”.
•
If the brake fluid level in the reservoir is too low, this could
result in an accident. Do not drive on. You should obtain profes-
sional assistance.
•
If the brake warning lamp lights up together with the ABS
warning lamp, this can mean that the control function of the ABS
is out of action. As a result the rear wheels can lock relatively
SET
SET
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Driver information system33
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data easily when braking. This could cause the tail of the vehicle to skid
sideways. Drive carefully to the nearest qualified workshop and
have the fault rectified.
Note
The warning lamp
 in the instrument cluster will start flashing as
well if there is a fault in the brake system.
Fault in the cooling system

Faults in the cooling system must be rectified immedi-
ately.If the
 symbol flashes in the display, this means that
either the coolant temperature is too high or the coolant
level is too low. The symbol is accompanied by a driver
message giving you more information about the fault. This
message will disappear after about 5 seconds, but you can
call it up again at any time by pressing the button:
Switch off engine, check coolant level
–Stop the vehicle.
– Switch off the engine.
– Check the coolant level ⇒page 261.
– Add more coolant if necessary ⇒page 261.
– Wait for the symbol to go out before driving on.
– Obtain professional assistance if necessary.
If the coolant level is correct, the overheating may be caused by a
malfunction of the radiator fan.If the alternator warning lamp lights up as well ⇒page 32, it is
possible that the drive belt has broken.
WARNING
•
If your vehicle should break down for technical reasons, stop it
at a safe distance away from moving traffic, switch off the engine
and turn on the hazard warning lights ⇒page 61, “Hazard
warning lights ”.
•
Never open the bonnet if you can see or hear steam or coolant
escaping from the engine compartment; there is a risk of being
scalded. Wait until you can no longer see or hear escaping steam
or coolant.
•
The engine compartment of any motor vehicle is a dangerous
place. Before carrying out any work in the engine compartment,
switch off the engine and allow it to cool down. Please observe the
important safety warnings ⇒page 255, “Working on components
in the engine compartment”.Caution
Do not drive on if the symbol
 has come on to indicate a fault in
the cooling system, otherwise there is a risk of damaging the
engine.
Engine oil pressure too low

If the engine oil pressure is too low the fault must be recti-
fied immediately.If the

symbol flashes in the display, the oil pressure is
too low. The symbol is accompanied by a driver message
giving you more information about the fault. This message
WARNING (continued)
SET
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Heating and cooling93
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Heating and coolingDeluxe automatic air conditionerApplies to vehicles: with deluxe automatic air conditionerDescription
The air conditioner can be used to set a comfortable inte-
rior temperature in the vehicle.The air conditioner provides heating and ventilation and also cools
and dehumidifies the air inside the vehicle.
The air conditioner is fully automatic and will maintain the desired
temperature at a constant level. To achieve this, the temperature of
the air supplied to the interior, the blower speed (volume of air
delivery) and the air distribution are regulated automatically. The
system also allows for the effect of strong sunlight, so there is no
need for manual adjustment. For these reasons it is advisable to use
the automatic mode for the comfort of all the passengers in virtually
all conditions throughout the year ⇒page 95.
Please note:
The humidity of the air is automatically reduced when the system
cools the interior of the vehicle. This helps to prevent condensation
on the windows.
If the humidity and temperature outside the vehicle are high,
condensation can drip off the evaporator in the air cooling system
and form a pool underneath the vehicle. This is normal and does not
indicate a leak.
If the outside temperature is low, the blower normally only switches
to a higher speed once the coolant has warmed up sufficiently (this
does not apply to the defrost setting).
In order to achieve maximum engine power, the air conditioner
compressor is temporarily switched off when pulling away from a
standstill with full throttle.The compressor also switches off if the coolant temperature is
excessively high, to ensure adequate engine cooling under extreme
loads.
Pollution filter
The pollution filter (a particle filter) serves as a barrier against impu-
rities in the outside air, including dust and pollen, and odours. The
air is also filtered when the air recirculation mode is activated.
For the air conditioner to work with maximum efficiency, the pollu-
tion filter element must be replaced at the intervals specified in the
Service Schedule.
If the vehicle is driven in areas with a high level of air pollution and
the filter is no longer fully effective, it may be necessary to change
the filter element more frequently.
Key-coded settings
The currently selected air conditioner settings are automatically
stored and assigned to the remote control key.
Power management
To prevent the battery from becoming discharged and to maintain
the necessary power level, the system will temporarily shut off the
electrical components that are using a lot of power, or reduce the
current they are consuming ⇒page 226. Heating systems in partic-
ular use a large amount of electrical power. If you notice, for
instance, that the rear window heater is not working, it may have
been temporarily switched off by the power management function,
or regulated to a lower heat output. These systems will be available
again as soon as sufficient electrical power is available.
WARNING
For safety reasons it is important that all the windows are kept
free of ice, snow and condensation. These can cause poor visibility
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Heating and cooling101
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
Applies to vehicles: with diesel engineSupplementary heater– Set the Supplementary heater to auto or off.Models with a diesel engine are equipped with a supplementary
heater to help warm up the interior more quickly. At outside temper-
atures below about +5 °C the supplementary heater is switched on
(and off) automatically when the engine is running, depending on
the coolant temperature, the temperature in the vehicle interior and
the temperature the heater is set to.Deluxe automatic air conditioner plusApplies to vehicles: with deluxe automatic air conditioner plusDescription
The air conditioner is designed to keep the passenger
compartment at the temperature you find most comfort-
able at all times of the year.The air conditioner provides heating and ventilation and also cools
and dehumidifies the air inside the vehicle.
The air conditioner is fully automatic, and will maintain the desired
temperature at a constant level. To achieve this, the temperature of
the air supplied to the interior, the blower speed (volume of air
delivery) and the air distribution are regulated automatically. The
system also allows for the effect of strong sunlight, so there is no
need for manual adjustment. For these reasons it is advisable to use
the automatic mode for the comfort of all the passengers in virtually
all conditions throughout the year ⇒page 103.
Please note:
The humidity of the air is automatically reduced when the system
cools the interior of the vehicle. This helps to prevent condensation
on the windows.If the humidity and temperature outside the vehicle are high,
condensation can drip off the evaporator in the air cooling system
and form a pool underneath the vehicle. This is normal and does not
indicate a leak.
If the outside temperature is low, the blower normally only switches
to a higher speed once the coolant has warmed up sufficiently (this
does not apply to the defrost setting).
In order to achieve maximum engine power, the air conditioner
compressor is temporarily switched off when pulling away from a
standstill with full throttle.
The compressor also switches off if the coolant temperature is
excessively high, to ensure adequate engine cooling under extreme
loads.
Pollution filter
The pollution filter (a combined particle filter and activated charcoal
filter) serves as a barrier against impurities in the outside air,
including dust and pollen, and against unpleasant smells. The air is
also filtered when the air recirculation mode is activated.
For the air conditioner to work with maximum efficiency, the pollu-
tion filter element must be replaced at the intervals specified in the
Service Schedule.
If the vehicle is driven in areas with a high level of air pollution and
the filter is no longer fully effective, it may be necessary to change
the filter element more frequently.
Key-coded settings
The currently selected air conditioner settings are automatically
stored and assigned to the remote control key.
Power management
To prevent the battery from becoming discharged and to maintain
the necessary power level, the system will temporarily shut off the
electrical components that are using a lot of power, or reduce the
current they are consuming ⇒page 226. Heating systems in partic-
ular use a large amount of electrical power. If you notice, for
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Checking and topping up fluids 260
Caution•
The oil level must never be above area ⇒page 258, fig. 254,
as this may result in damage to the catalytic converter or to the
engine. On vehicles without an oil dipstick, you can check the oil
level via the sound system or MMI*. Contact a qualified workshop to
extract the engine oil if necessary.
•
No additives should be used with engine oil. Any damage caused
by the use of such additives would not be covered by the factory
warranty.For the sake of the environment
•
Never pour oil down drains or into the ground.
•
Always observe statutory requirements when disposing of
empty oil canisters.
Cooling systemCoolant
The purpose of the coolant is to carry heat away from the
engine. The correct amount of anti-freeze is important to
prevent the cooling system from freezing in winter.The cooling system is filled for life at the factory, so the coolant does
not need to be changed. The coolant consists of a mixture of water
and anti-freeze additive G12++. This is a glycol-based anti-freeze
with anti-corrosion additives.
Anti-freeze additive
The amount of anti-freeze additive required depends on the temper-
atures to be expected in the winter season. If the anti-freeze concen-
tration is too low the coolant can freeze, resulting in failure of the
cooling system and heater.The cooling system is filled at the factory with the correct amount of
anti-freeze for the country concerned.
In most cases the mixture consists of 60% water and 40% additive.
This mixture gives the required anti-freeze protection at tempera-
tures down to -25 °C and protects the alloy parts of the cooling
system against corrosion. It also prevents scaling and raises the
boiling point of the coolant.
Countries with warm climate
The coolant concentration must not be reduced by adding plain
water, even in the summer or in warm climates. The concentration
of the anti-freeze additive must always be at least 40%.
Countries with cold climate
If greater anti-freeze protection is required in very cold climates, the
proportion of the anti-freeze additive G12++ can be increased. A
concentration of 60% offers protection down to about - 40 °C. The
concentration of the anti-freeze additive must not be more than
60%, otherwise this would reduce the anti-freeze protection. In addi-
tion, the cooling effect will be adversely affected.
Vehicles for export to countries with a cold climate (such as Sweden,
Norway and Finland) are supplied with antifreeze protection down
to about -35 °C. The concentration of the antifreeze additive for
these countries should always be at least 50%.
Caution
•
It is advisable to have the cooling system checked before the
winter season to make sure that the antifreeze concentration is
adequate for the conditions to be expected. This applies particularly
if you intend to take the car into a colder climate zone. If necessary,
have the anti-freeze concentration increased to 50 - 60% as required.
•
Use only anti-freeze additive G12++, an additive meeting the
specification “TL 774 G”. Other additives may give considerably
inferior corrosion protection. The resulting corrosion in the cooling
system can lead to a loss of coolant, causing serious damage to the
engine.
Aa
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Checking and topping up fluids261
Controls
Safety
Driving tips
General maintenance
Self-help
Technical data
•
The coolant additive G12++ can be mixed only with additives
G12+ and G12.
Checking coolant level
The coolant level can be checked at a glance.– Switch off the ignition.
– Read off coolant level on radiator expansion tank
⇒fig. 257. When the engine is cold it should be between
the “MIN” and “MAX” marks. When the engine is hot it
may be slightly above the “MAX” mark.The coolant level should be checked with the engine switched off.
The coolant level is monitored by a warning lamp in the instrument
cluster ⇒page 33. However, we recommend that it should be
checked occasionally.
Coolant losses
Any loss of coolant normally indicates a leak in the cooling system.
In this case the cooling system should be inspected by a qualified
workshop without delay. It is not sufficient merely to top up the
coolant.If there are no leaks in the system, a loss of coolant can only occur
if the coolant boils and is forced out of the system as a result of
overheating.
Caution
Radiator sealants must not be added to the coolant. Such additives
could seriously impair the function of the cooling system.Topping up the coolant
Be careful when topping up coolant.– Switch off the engine.
– Wait for the engine to cool down.
– Cover the cap on the expansion tank ⇒fig. 257 with a
cloth, and carefully unscrew the cap anti-clockwise
⇒.
– Add coolant.
– Screw the cap on again tightly.Make sure that the coolant meets the required specifications
⇒page 260, “Coolant”. Do not use a different type of additive if anti-
freeze additive G12++, G12+ or G12 is not available. In this case use
only water and bring the coolant concentration back up to the
correct level as soon as possible by putting in the specified additive.
Always top up with fresh, unused coolant.
Do not fill above the “MAX” mark. Excess coolant is forced out of the
system through the valve in the filler cap when the engine gets hot.
If a lot of coolant has been lost, wait for the engine to cool down
before putting in cold coolant. Failure to do so could result in
serious engine damage.
Fig. 257 Engine
compartment: Mark-
ings on radiator expan-
sion tank
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