2018 AUDI A8 radiator cap

Checking and Filling
Emissions control
systems
Catalytic converter
A pp lies to: ve hicles w ith gasoline engines
The vehicle may on ly be driven with unleaded
gasoline, otherwise the catalyt ic converter will be
destroyed.
Never d rive until the tank is comp letely empty .
The irregular supp ly of f uel that results from that
can cause engine m isfires. Uncombusted fuel will
enter the exhaust system , w hich can cause over­
heating and damage to the catalyt ic converter .
A WARNING
The temperature o f the exha ust system is
hig h, bo th whe n driving and after stopping
t he engine.
-
- Never touch the exha ust ta il pi pes once they
h ave become ho t. This could resul t in burns.
- Do no t park you r vehicle ove r flammable
m aterials such as g rass or leaves because
t h e hi gh te mperat ure of the emiss io ns con­
t rol sys te m c ould star t a fire.
- D o no t apply u nder bod y p rote ctant in the
exha ust syste m are a, bec au se t his in cre ases
t h e ris k of fire .
Engine compartment
Working in the engine compartment
Special core is required if you ore working in the
engine comportment
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 on the vehicle .
~ ,&..
A WARNING
- T urn the engine off.
- Switch the ign ition off .
- Set the parking b rake .
- Select the P selector leve r pos ition.
272
- Let the eng ine cool down .
- Never open the hood when there is steam o r
coo lant escapin g from the engine compart­
ment, because there is a risk that yo u could
be burned. Wait unt il no steam or coolant is
escaping.
- Keep children away from the eng ine com­
pa rtment.
- Never sp ill fluids on a hot engine. These flu­
ids (such as the anti-freezing agent con­
tained in the coolant) can ignite .
- Avoid short c ircuits in the electrical system.
- When working in the engine compa rtment,
remember that the radiator fan can switch
on even if the ignition is switched off, wh ich
increases the r isk of persona l injury.
- Never open the cap on the coolant expan­
sion tank when the engine is warm. The
cooli ng system is under p ressure .
- To protect your face, hands, and a rms from
hot steam or coolant, cover the cap with a
large cloth when opening.
- Do not remove the engine cove r under any
circumstances . T his increases the risk of
burns.
- If tests need to be perfo rmed with the en­
gine running, there is add itiona l danger due
to mov ing components (such as the r ibbed
be lt, alterna tor and rad iator fan) and from
the high-voltage ignition system.
- Do not unde r any circ ums tances activate the
throttle inadvertently (for example, by hand
from t he e ngine compartment) if the veh i­
cle is stat ionary but the en gine is r un ning
an d a gea r is en gaged. Otherwise, the veh i­
cle will start to move immediately and this
could result in an acc ident .
- Pay a ttent ion to the following wa rnings lis t­
e d w hen wor k on the fue l system o r on the
electrical equipment is require d.
- Do no t smoke.
- Never work near open flames .
- Always have a working fire extinguisher
nearby.
- All work on the battery or elect rical system
in your vehicle can result in injuries, chemi ­
cal b urns, acc idents or bu rns. Because o f
this, all work m ust be perfo rmed
only b y an ~

Checking and Filling
If you must add coolant, use a mixture of water
and coolant additive . Mixing the coolant additive
with distilled water is recommended.
Coolant additive
The coolant additive is made of anti-freezing and
corros ion protection agents. Only use the follow ­
ing coo lant additives .
Coolant additive Specification
Gl2evo
TL 774 L
Gl2++ TL 774 G
Gl3
TL 774 J
These additives may be mixed wi th each othe r.
The amount of coo lant additive that needs to be
mixed with water depends on the climate where
the vehicle will be operated. If the coolant addi ­
tive percentage is too low, the coo lant can free ze
and damage the engine.
Coolant addi- Freeze protec-
tive tion
Warm regions min.
40%, min. -13 °F
max . 45% (-25 °()
C old regions min.
50%, max. -40 °F
max.
55% (-40 °C)
@ Note
-Before the start of winter, have an author­
ized Audi dealer or authorized Audi Service
Faci lity 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 appropriate coolant additive is not
available in an emergency, do not add any
other addit ive for risk of damaging the en­
g ine . If this happens, only use water and re­
store 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 w ith
the coolant.
278
Adding coolant
Fig. 260 Eng in e compar tment : coolant exp ansion tank
cover
Observe the safety precautions ~.&, in Working
in the engine compartment on page 2
72.
Checking the engine coolant level
~ Park the vehicle on a level surface .
~ Switch the ignit io n off.
~ Read the coolant level on the coolant expansion
tank ~ page 2 74. The coolant leve l must be be­
tween the MIN and MAX markings when the en­
gine in co ld. When the engine is warm it can be
slightly above the MAX marking,
Adding coolant
Requirement: there must be a residual amount of
coolant in the expansion
tank ~(©) .
~ Let the engine cool down .
~ Place a cloth over the coolant expansion tank
cap and unscrew the cap counterclockwise
~.&. -
~ Add coo lant mixed in the correct ratio
~ page 277 up to the MAX marking.
~ Make sure that the f luid level remains stable.
Add more coolant if necessary .
~ Close the cap securely .
Coo lant loss usually indicates there is a leak . Im ­
mediate ly drive your vehicle to an authorized
Audi dealer or authorized Audi Service Fac ility
and have the cooling system inspected. If the
cooling system is not leaking, a loss can come
from the coolant bo iling t hrough overheat ing
and being pushed out of the cooling system .

lL
_& WARNING
-The cooling system is under pressure. Do
not open the coolant expansion tank cap
when the engine is hot. This increases the
risk of burns .
- The coolant additive and the coolant can be dangerous to your health. For this reason,
keep the coolant in the original container
and away from children. There is a risk of
poisoning.
- 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.
CD Note
Do not add coolant if the expansion tank is
empty. Air could enter the cooling system and
damage the engine. If this is the case, do not
continue driving. See an authorized Audi deal­
er or authorized Audi Service Facility for assis­
tance.
Brake fluid
N N
-N
" co IX)
Fig. 261 Engine compartment: cap on brake flu id reservoir
Observe the safety precautions ~&. in Working
in the engine compartment on page 2
72.
Checking the brake fluid level
.. Read the brake fluid level on the brake fluid
reservoir
~ page 274, fig. 258. The brake fluid
level must be between the MIN and MAX mark­
ings~&. -
~ The brake fluid level is monitored automatically .
...... N ...... 0 0 :c ' Checking and Filling
Changing the brake fluid
Have the brake fluid changed regularly by an au­
thorized Audi dealer or authorized Audi Service
Facility.
_& WARNING
-
- If the brake fluid level is below the MIN
marking, it can impair the braking effect
and driving safety, which increase the risk of
an accident . Do not continue driving . See an
authorized Audi dealer or authorized Audi
Service Facility for assistance.
- If the brake fluid is old, bubbles may form
in the brake system during heavy braking.
This would impair braking performance and
driving safety, which increases the risk of an
accident.
- To ensure the brake system functions cor­
rectly, only use brake fluids that comply
with VW standard 50114 or FMVSS-116 DOT 4.
CD Note
- If the brake fluid level is above the MAX
marking, brake fluid may leak out over the
edge of the reservoir and result in damage
to the vehicle.
- Do not get any brake fluid on the vehicle
paint, because it will corrode the paint.
Battery
General warnings about batteries
Because of the complex power supply, all work
on batteries such as disconnecting, replacing,
etc., should
only be performed by an authorized
Audi dealer or authorized Audi Service Facility
~ .&. .
The term "vehicle battery" refers to the 12 Volt
battery in your vehicle.
Detailed warnings for the vehicle battery:
® Wear eye protection.
b. Bat~ery acid is highly corrosive. Wear pro-
~ tect1ve gloves and eye protection. Ill>-
279