2021 AUDI A8 engine overheat

Instrument cluster

Reducing the display
Depending on the vehicle equipment, you can
hide the central area in the instrument cluster.
> Select on the instrument cluster: vehicle func-
tions tab > E] button > Reduced display.
Coolant temperature
display
Applies to: vehicles with a coolant temperature indicator
The coolant temperature display @ > page 12
only functions when the ignition is switched on.
To reduce the risk of engine damage, please ob-
serve the following notes about the temperature
ranges.
Cold range
If only the LEDs at the bottom of the gauge turn
on, the engine has not reached operating tem-
perature yet. Avoid high engine speeds, full accel-
eration, and heavy engine loads.
Normal range
The engine has reached its operating tempera-
ture once the LEDs up to the center of the gauge
turn on. If the | indicator light in the instru-
ment cluster display turns on, the coolant tem-
perature is too high > page 281.
@) Note
— Auxiliary headlights and other accessories in
front of the air intake impair the cooling ef-
fect of the coolant. This increases the risk of
the engine overheating during high outside
temperatures and heavy engine load.
— The front spoiler also helps to distribute
cooling air correctly while driving. If the
spoiler is damaged, the cooling effect will
be impaired and the risk of the engine over-
heating will increase. See an authorized
Audi dealer or authorized Audi Service Fa-
cility for assistance.
Tachometer
The tachometer (@) 9 page 12 displays the engine
speed in revolutions per minute (RPM). The be-
ginning of the red zone in the tachometer indi-
14
cates the maximum permissible engine speed for
all gears once the engine has been broken in. Be-
fore reaching the red zone, you should shift into
the next higher gear, select the "D" or "S" selec-
tor lever position, or remove your foot from the
accelerator pedal.
Displaying the tachometer
Applies to: vehicles with plug-in hybrid drive
> Applies to: MMI: Select on the home screen:
SETTINGS > Display & brightness > Audi virtu-
al cockpit > Left dial > Tachometer or Com-
bined.
Engine speed limitation
If the Bw indicator light turns on, the engine will
be automatically limited to the RPM displayed in
the instrument cluster. This will protect the en-
gine components, for example during a cold start
or from overheating.
The engine speed limitation is deactivated if you
release the accelerator pedal while the engine is
at normal operating temperature.
If the engine speed limitation was activated by
an engine control malfunction, the indicator
light also turns on. Make sure the engine speed
does not go above the speed displayed, for exam-
ple when downshifting. Drive to an authorized
Audi dealer or authorized Audi Service Facility im-
mediately to have the malfunction corrected.
C) Note
The needle in the tachometer may only be in
the red area of the gauge for a short period of
time before there is a risk of damaging the
engine. The location where the red zone be-
gins varies depending on the engine.

4N0012721BF
Driving

Set the parking brake before selecting the “P” se-
lector lever position. This prevents too much
stress from being placed on the locking mecha-
nism when parking on a steep surface.

ZX WARNING
— Always set the parking brake when leaving
your vehicle, even if for a short period of
time. If the parking brake is not set, the ve-
hicle could roll away, increasing the risk of
an accident.
— Do not leave your vehicle unattended while
the engine is running, because this increases
the risk of an accident.
— If the parking brake is set, it can release au-
tomatically when the accelerator pedal is
pressed. To reduce the risk of an accident,
do not inadvertently press the accelerator
pedal and always shift into “P” when the ve-
hicle is stopped.
— If you leave the vehicle, switch the ignition
off and take the key with you. This is espe-
cially important when leaving persons or an-
imals in the vehicle. Otherwise, the vehicle
could start unintentionally, the parking
brake could release, or electronic equipment
could activate, which increases the risk of an
accident.
— No persons or animals should be left in a
locked vehicle. Locked doors make it more
difficult for emergency workers to enter the
vehicle, which puts lives at risk.
— If you do not begin driving immediately af-
ter releasing the brake pedal, your vehicle
may begin to roll backward. Press the brake

pedal or set the parking brake immediately.

@) Note
If you have to stop on an incline, always press
the brake pedal to hold the vehicle in place to
reduce the risk of the vehicle rolling back-
ward. Do not try to hold the vehicle in place
by pressing and holding the accelerator pedal.
The transmission can overheat, which increas-
es the risk of damage.
Hill hold assist
If you take your foot off of the brake pedal when
driving on hills, the braking force will be held for
several seconds. At that time, you can start driv-
ing without the vehicle rolling backward.
Requirement: the driver's door must be closed,
the engine must be on, and the vehicle must be
traveling uphill.
> To activate hill hold assist, press and hold the
brake pedal for several seconds while the vehi-
cle is stationary.

Z\ WARNING
— If you do not begin driving immediately af-
ter releasing the brake pedal, your vehicle
may begin to roll backward. Press the brake
pedal
or set the parking brake immediately.
— The hill hold assist cannot hold the vehicle
on inclines in every scenario (for example,
on slippery or icy ground).
Gears and driving programs
(1)
(2S




[RAZ-0410



R
N
:
D/S
~— SI
Fig. 92 Center console: selector lever


The automatic transmission shifts automatically
depending on the selected gear and the current
driving style. When driving with a moderate driv-
ing style, upshifting early and downshifting late
will help to improve fuel economy. When driving
with a sporty driving style, the transmission per-
mits higher RPMs.
The gears are displayed next to the selector lever.
— P (Park)
— R (Reverse): driving in reverse
—N (Neutral): idle
109

Driving

— The braking force generated by the pressed
brake pedal is greater than the braking force
that
would be initiated by the system
— The ESC, the brake system, or the vehicle elec-
trical system is not functioning

ZA WARNING
— Only apply the brakes for the purpose of
cleaning the brake system when road and
traffic conditions permit. You must not en-
danger other road users and increase the
risk of an accident.
— Due to the risk of injury, only have an au-
thorized Audi dealer or authorized Audi
Service Facility work on the brake system.
Incorrect repairs could impair the function.
— Never let the vehicle roll while the engine is
stopped because this increases the risk of an
accident.
— During automatic braking maneuvers, the
brake pedal may move downward automati-
cally. To reduce the risk of injury, do not
place your foot under the brake pedal.
@) Note
— Never let the brakes “rub” by pressing the
pedal lightly when braking is not actually
necessary. This can cause the brakes to over-
heat and increases braking distance and
causes wear.
— Observe the important information for driv-
ing downhill > page 122. This especially ap-
plies when towing a trailer.
G@) Tips
— If you retrofit your vehicle with a front spoil-
er, wheel covers or similar items, make sure
that the air flow to the brakes is not ob-
structed. Otherwise the brake system can
overheat.

— Also refer to the information about brake
fluid > page 283.
Messages
GG i @ Brakes: malfunction! Stop vehicle
safely
120
There is a malfunction in the brake system. If
[S/ Bana B also turn on, there is a malfunc-
tion in the ABS, ESC, and braking distribution. If
the brake booster is not working, you have to use
much more force when braking the vehicle.
Do not continue driving. See an authorized Audi
dealer or authorized Audi Service Facility for as-
sistance. Read and follow the other safety pre-
cautions > A\.
fie 7 © Brake pads: wear limit reached. You
can continue driving. Please contact Service
The brake pads are worn. Drive to an authorized
Audi dealer or authorized Audi Service Facility as
soon as possible to have the malfunction correct-
ed.
Brake booster: limited functionality. You can
continue driving. Please contact Service
There is a brake booster malfunction. The brake
booster is available, but its effectiveness is re-
duced. The braking performance may be different
compared to the usual performance. Drive to an
authorized Audi dealer or authorized Audi Service
Facility immediately to have the malfunction cor-
rected.
Brake booster: deactivated. See owner's manual
The brake booster remains active for a brief peri-
od of time after switching off the ignition. Secure
the vehicle against rolling > page 108.
Other indicator lights
When you switch the ignition on, the GG / @®
indicator light turns on briefly to check the func-
tion. If the indicator light does not turn on, there
is a system malfunction.
1f Ba / @ stays on, there is a malfunction in
the brake system.
@- A high load was placed on the brakes from
driving downhill for a long period of time. Follow
the instructions in the message to utilize the en-
gine braking effect and to relieve the brakes.

ZA WARNING
If a malfunction occurs in the ABS, ESC, and
braking distribution, interventions that >

4N0012721BF
Driver assistance

Driver assistance
Cruise control system
Applies to: vehicles with cruise control system
The cruise control system assists the driver in
maintaining a constant speed above approxi-
mately 15 mph (20 km/h). The system maintains
the desired speed by braking and accelerating.
Switching the system on
Applies to: vehicles with cruise control system


ZA WARNING
— Always pay attention to the traffic around
your vehicle when the cruise control system
is in operation. As the driver, you are always
responsible for controlling your vehicle
speed and the distance between your vehicle
and
other vehicles.
— For safety reasons, cruise control should not
be used in the city, in stop-and-go traffic, on
winding roads, and when road conditions are
poor (such as ice, fog, gravel, heavy rain,
and conditions that could lead to hydroplan-
ing), because this increases the risk of an ac-
cident.
— Switch the cruise control off temporarily
when driving in turning lanes, highway exits,
or in construction zones.
—To reduce the risk of an accident, you should
only resume the stored speed if it is suitable
for the current traffic conditions.
BFV-0220



() Note
— Conventional drive system:Before driving
downhill a long distance on a steep hill, de-
crease your speed and select a lower gear.
This makes use of the engine braking effect
and reduces the load placed on the brakes.
— Plug-in hybrid drive: Before driving downhill
a long distance on a steep hill, decrease
your speed and use the recuperation braking
effect > page 114. This reduces the load on
the brakes.
@ Tips
The brake lights turn on when the brakes are
applied automatically.


Fig. 116 Operating lever: switching the system on
Requirement: the ignition must be switched on.
> To switch the system on, pull the lever toward
you to position ©.
The Gia or i$) indicator light and the corre-
sponding message will appear in the instrument
cluster.

ZA\ WARNING
If the brakes are malfunctioning (for example,
overheating) while the cruise control system
is switched on, the regulating functions may


shut off automatically.


Preselecting or activating a cruise con
speed
Applies to: vehicles with cruise control system
When the vehicle is stationary, you can preselect
the cruise control speed or activate the speed
while driving.
Requirement: the system must be switched on.
> To preselect a cruise control speed when the ve-
hicle is stationary, tap the lever toward @)/G)
=> page 163, fig. 116.
> To activate the cruise control speed, pull the
lever
toward position @ while driving.
> To set the current driving speed as the cruise
control speed, press the button @) on the lever.
The active cruise control speed is indicated with
the Gg or kl indicator light in the instrument
cluster.
163
>

Checking and Filling

cause overheating and damage to the catalytic
converter.
Malfunction Indicator Lamp (MIL)
If the S indicator light blinks or turns on, there
is a malfunction that is causing poor emissions
quality and that could damage the catalytic con-
verter. Drive slowly to an authorized Audi dealer
or authorized Audi Service Facility to have the
malfunction corrected.
The indicator light can also turn on if the fuel fill-
er cap is not closed correctly > page 271).
Engine compartment
General information
Special care is required if you are working in the
engine compartment
For work in the engine compartment, such as
checking and filling fluids, there is a risk of in-
jury, scalding, accidents, and burns. For this
reason, follow all the warnings and general
safety precautions provided in the following in-
formation. The engine compartment is a dan-
gerous area in the vehicle. > A.
Explanation of warnings (sticker in the engine
compartment):
®

Hot engine components!
Rotating parts!

The catalytic converter can be damaged
"127i if the oil level is too high!

Always follow the instructions in the op-
oA erating manual.



The radiator fan can switch on at any
i, time!

High voltage! Switch off the engine be-
5 fore coming into contact with any igni-
tion system components!



Applies to: vehicles with plug-in hybrid
drive: High voltage! The voltage in the
high-voltage system is high enough to
EN cause fatal injuries. Touching a damaged
high-voltage component can result in a
fatal electric shock.


D_ Depending on the engine and country
274

ZA\ WARNING
— Turn the engine off.
— Switch the ignition off.
— Set the parking brake.
— Select the “P” (Park) selector lever position.
— Allow the engine to cool.
— Keep children away from the engine com-
partment.
— Never spill fluids on a hot engine. These flu-
ids (such as the freeze protection contained
in the coolant) can catch fire.
— Avoid short circuits in the electrical system.
— Never reach into the radiator fan. The fan is
temperature-controlled and can turn on
suddenly, even when the ignition is switched
off.
— Never open the hood when there is steam or
coolant escaping from the engine compart-
ment, because there is a risk that you could
be burned. Wait until no steam or coolant is
escaping.
— Plug-in hybrid drive: The coolant expansion
tank cap is equipped with a seal that must
never be removed under any circumstances
= page 277, fig. 181. If the coolant expan-
sion tank for the high-voltage system is not
sealed, please contact an authorized Audi
dealer or authorized Audi Service Facility.
— Plug-in hybrid drive: The sealed cap must
only be opened by an authorized Audi dealer
or authorized Audi Service Facility.
—The cap on the coolant expansion tank must
never be opened when the coolant is hot.
The cooling system is under pressure. There
is a risk of burns
—To protect your face, hands, and arms from
hot steam or coolant, cover the cap with a
thick cloth when opening.

4N0012721BF
Checking and Filling

> Push the release button again and remove the
cap completely.
> Add coolant mixed in the correct ratio
=> page 281 up to the MAX marking.
> Make sure that the fluid level remains stable.
Add more coolant if necessary.
> Turn the cap to the right to tighten it until you
feel resistance a second time.
Coolant loss usually indicates that there is a leak.
Immediately drive your vehicle to an authorized
Audi dealer or authorized Audi Service Facility
and have the cooling system inspected. If the
cooling system is not leaking, coolant loss can re-
sult from the coolant boiling due overheating
and then being forced out of the cooling system.

der any circumstances > page 277, fig. 181.
If the coolant expansion tank for the high-
voltage system is not sealed, please contact
an authorized Audi dealer or authorized
Audi Service Facility.
— When adding coolant, it may leak into the
inside of high-voltage components and
cause a short circuit, increasing the risk of

fire.


ZA WARNING
— The engine compartment in any vehicle is a
potentially dangerous area. Stop the engine,
switch the ignition off, and allow the engine
to cool before working in the engine com-
partment. Always follow the information
found in > page 274, General information.
— Never open the hood if you can see or hear
steam or coolant escaping from the engine
compartment. This increases the risk of
burns. The cooling system is under pressure.
When you no longer see or hear steam or
coolant escaping, you may open the engine
compartment with caution.
— When working in the engine compartment,
remember that the radiator fan can switch
on even if the ignition is switched off, which
increases the risk of injury.
— Coolant additive and coolant can be danger-
ous to your health. For this reason, store the
coolant in the original container and away
from children. There is a risk of poisoning.
CG) Note
Do not continue driving if the coolant expan-
sion tank is empty. Do not add any coolant,
because air could enter the cooling system
and damage the engine. See an authorized
Audi dealer or authorized Audi Service Facility
for assistance.
Brake fluid

BFV-0229|




ZA WARNING
Applies to: vehicles with plug-in hybrid drive
The coolant expansion tank for the high-volt-
age system may only be opened or filled by an
authorized Audi dealer or authorized Audi
Service Facility.
— The coolant expansion tank cap is equipped
with a seal that must never be removed un-


Fig. 184 Engine compartment: cap on brake fluid reservoir
Observe the safety precautions > page 274, Gen-
eral information.
Checking the brake fluid level
> Slide the cover that is located below the wind-
shield wipers on the driver's side toward the
windshield and remove the cover.
> Read the brake fluid level on the brake fluid res-
ervoir > page 277, fig. 181. The brake fluid lev-
el must be between the MIN and MAX markings
oA.
The brake fluid level is monitored automatically.
Messages
EG 7 @ Brakes: stop vehicle and check brake
fluid level
283
>

4N0012721BF
Checking and Filling

should only be performed by an authorized Audi
dealer or authorized Audi Service Facility > A\.
Multiple batteries with different technologies
may be installed in your vehicle:
— Vehicle battery (for example, for starting the
engine, basic power supply) > page 285, 12
Volt vehicle battery or > page 286, Other bat-
tery types
— Auxiliary battery (for example, for recuperation
or optional equipment) > page 286, Other bat-
tery types
— Plug-in hybrid drive: High-voltage battery (for
example, for electric driving) > page 131, In-
troduction.
Not running the vehicle for long periods of
time
The battery will gradually drain if the vehicle
does not run for long periods of time. To ensure
that the vehicle can still be started, the electrical
equipment will be limited or switched off. Some
convenience functions, such as interior lighting
or power seat adjustment, may not be available
under certain circumstances. The convenience
functions will be available again when you start
the
engine.
Even when electrical equipment is switched off,
the equipment can still drain the battery if the
vehicle is not driven for long periods of time.
Deep draining results in a chemical reaction that
destroys the inside of the battery. The battery
must be charged every month to prevent this
= page 286. Contact an authorized Audi dealer or
authorized Audi Service Facility for more infor-
mation.
Winter operation
Cold weather places an especially high load on
the 12 Volt vehicle battery. Have the battery
checked by an authorized Audi dealer or author-
ized Audi Service Facility before cold weather be-
gins.

this, all work must be performed only by an
authorized Audi dealer or authorized Audi
Service Facility.
— Never connect a charging cable or jump
start cable directly to the 12 Volt vehicle
battery. Only use the connections in the en-
gine compartment > page 286.

Z\ WARNING
California Proposition 65 Warning:
— Battery posts, terminals and related acces-
sories contain lead and lead compounds,
chemicals known to the State of California
to cause cancer and reproductive harms.
Wash hands after handling.
@) Note
— If the vehicle will be parked for long periods
of time, protect the battery against the cold
so that it will not be destroyed by “freezing”
=> page 286, Charging the 12 Volt vehicle
battery.
— There are electrical components under the
cargo floor behind a trim panel that warm
up during operation. To reduce the risk of
the components overheating, do not store
objects such as blankets under the cargo
floor. If the components overheat, they will
switch off temporarily. This will be indicated
by a message that will be displayed in the
instrument cluster until the temperature re-
turns to normal.
12 Volt vehicle battery
Explanation of warnings:


Always wear eye protection.

Battery acid is highly corrosive. Always
wear protective gloves and eye protection.

Fire, sparks, open flame, and smoking are
forbidden.

Z\ WARNING
— All work on the battery or electrical system
in your vehicle can result in injuries, chemi-
cal burns, accidents, or burns. Because of

A highly explosive mixture of gases can
form when charging batteries. >
@
>
©

285