2021 AUDI A8 radiator cap

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.

Checking and Filling

@) Note
— Before the start of winter, have an author-
ized Audi dealer or authorized Audi Service
Facility check if the coolant additive in your
vehicle matches the percentage appropriate
for the climate. This is especially important
when driving in colder climates.
— If the G12evo coolant additive is not availa-
ble in an emergency, do not add any other
additive. You could damage the engine. If
this happens, only use distilled water and
restore the correct mixture ratio with the
specified coolant additive as soon as possi-
ble.
— Only refill with new coolant.
— Radiator sealant must not be mixed with
the coolant.
— You can continue driving if the permitted
G12evo coolant additive was not added.
However, go to an authorized Audi dealer or
authorized Audi Service Facility immediately
to have the coolant replaced to reduce the
risk of engine damage.
— Due to the risk of engine damage, the cool-
ing system should only be refilled by an au-
thorized Audi dealer or authorized Audi
Service Facility. An authorized Audi dealer or
authorized Audi Service Facility can also pro-
vide you with important information about
the recommended coolant additive.

RAZ-0540

MIN


Fig. 183 Engine compartment - Coolant expansion tank:
@ cover with release button; @) markings
Observe the safety precautions > page 274, Gen-
eral information.
282
Applies to: vehicles with plug-in hybrid drive:
Your vehicle has two coolant expansion tanks
that are separate from each other > page 277,
fig. 181. One expansion tank for the combustion
engine and one tank for the high-voltage system.
The coolant expansion tank for the high-voltage
system is sealed and must not be opened > /\
and> A\.
Checking the coolant level
> Park the vehicle on a level surface.
> Switch the ignition off.
> Open the hood > page 276.
> Check the coolant level in the coolant expan-
sion tank > page 277, fig. 181 using the outer
markings (2) > fig. 183. The coolant level must
be between the markings (2) when the engine is
cold. When the engine is warm it can be slight-
ly above the upper marking.
> Conventional drive system: When you add cool-
ant to the expansion tank, please refer to
=> page 281, Cooling system.
>» Plug-in hybrid drive: If you add coolant to the
coolant expansion tank for the combustion en-
gine, see > page 281, Cooling system.
» Plug-in hybrid drive: If coolant is missing from
the high-voltage system coolant expansion
tank, do not continue driving. Contact an au-
thorized Audi dealer or authorized Audi Service
Facility immediately > A\.
Adding coolant
Applies to: coolant expansion tank for combustion engine
When adding coolant to the combustion engine
expansion tank, please observe the following in-
structions.
Requirement: there must be a residual amount of
coolant in the expansion tank >@).
If you must add coolant, use a mixture of water
and coolant additive. Audi recommends mixing
the coolant additive with distilled water.
> Allow the engine to cool.
> Place a large, thick towel on the coolant expan-
sion tank cap.
> Push the release button @ > fig. 183 on the
cap and carefully turn it to the left until you
feel resistance > /\.

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

> Close the cover on the positive terminal.
> Close the hood > page 276.

ZA WARNING
— 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.
— A highly explosive mixture of gases can form
when charging batteries. Only charge the
battery in well-ventilated areas.
— A drained battery can freeze at tempera-
tures around 32 °F (0 °C). Do not charge or
use a frozen or thawed battery. If ice forms,
the battery housing can crack and battery
electrolyte can leak out, which increases the
risk of an explosion and chemical burns.
Contact an authorized Audi dealer or author-
ized Audi Service Facility for more informa-
tion.
— Do not connect or disconnect the charging
cable while charging because this increases
the risk of an explosion.

@) Tips
Read all of the manufacturer's instructions
for the charger before charging the battery.
Windshield washer
system

B4M-0135)

Fig. 186 Engine compartment: washer fluid reservoir cap
Observe the safety precautions > page 274, Gen-
eral information.
The windshield washer reservoir <> contains the
cleaning solution for the windshield and the
headlight washer system* > fig. 186,
= page 277. The reservoir capacity can be found
in > page 344.
To reduce the risk of lime scale deposits on the
spray nozzles, use clean water with low amounts
of calcium. Always add window cleaner to the wa-
ter. When the outside temperatures are cold, an
anti-freezing agent should be added to the water
so that it does not freeze.
Messages
|} Please add washer fluid
Fill the washer fluid for the windshield washer
system and the headlight washer system* when
the ignition is switched off.
CG) Note
—The concentration of anti-freezing agent
must be adjusted to the vehicle operating
conditions and the climate. A concentration
that is too high can lead to vehicle damage.
— Never add radiator anti-freeze or other addi-
tives to the washer fluid.
— Do not use a glass cleaner that contains
paint solvents, because this could damage
the paint.
Service interval display
The service interval display detects when your ve-
hicle is due for service.
The service interval display works in two stages:
— Inspection or oil change reminder: after driv-
ing a certain distance, a message appears in the
instrument cluster display each time the igni-
tion is switched on or off. The remaining dis-
tance or time is displayed briefly.
— Inspection or oil change due: if your vehicle
has reached an inspection or oil change interval
or both intervals at the same time, the mes-
sage Inspection due! or Oil change due! or Oil
change and inspection due! appears briefly af-
ter switching the ignition on or off.
Checking service intervals
You can check the remaining distance or time un-
til the next oil change or next inspection in the
Infotainment system.
287