2021 AUDI A8 engine

4N0012721BF
Checking and Filling

Checking and Filling
Fuel
Types of gasoline
The correct gasoline grade is stated on the inside
of the fuel filler door.
The vehicle is equipped with a catalytic converter
and must only be driven with unleaded gasoline.
Audi recommends using TOP TIER Detergent Gas-
oline. For additional information on TOP TIER De-
tergent Gasoline, visit www.toptiergas.com.
The individual gasoline grades are differentiated
by octane ratings. This value is given with (R
+M)/2 equating to AKI or in RON.
The headings below match the sticker in the fuel
filler door (examples):
UNLEADED FUEL ONLY MIN. (R+M)/2 87
Regular / MIN. RON 91 Regular
Use regular gasoline with minimum 87 AKI /
91 RON > ©.
Audi recommends using premium gasoline with
minimum 91 AKI/ 95 RON to achieve the rated
horsepower and torque.
UNLEADED FUEL ONLY PREMIUM MIN. (R
+M)/2 91 / SUPER MIN. RON 95
Using premium gasoline with minimum 91 AKI /
95 RON is recommended.
If premium gasoline is not available, you can also
use regular gasoline 87 AKI / 91 RON. However
this does reduce the engine power slightly.
UNLEADED FUEL ONLY PREMIUM MIN. (R
+M)/2 93 / SUPER PLUS MIN. RON 98
Using premium plus gasoline with at least 93
AKI / 98 RON is recommended.
If no premium plus gasoline is available, you can
also use premium gasoline with 91 AKI /95 RON.
However this does reduce the engine power
slightly.
CG) Note
— Filling the tank just one time with leaded
fuel or other metallic additives will cause
permanent deterioration to the catalytic
converter function.
— When gasoline with an octane rating that is
too low is used, high speeds or heavy engine
load can lead to engine damage.
@ Tips
The vehicle may be filled with fuel that has a
higher octane rating than what is required by
the engine.
Gasoline mixture
Gasoline with alcohol or MTBE (Methyl-Tert-
Butyl-Ether)
You can use unleaded gasoline mixed with alco-
hol or MTBE (generally labeled as oxygenated
compounds) as long as the fuel meets the follow-
ing conditions:
Gasoline with methanol content (methyl alco-
hol or methanol)
— Anti-Knock Index is at least 87 AKI
—No more than 3% methanol
— More than 2% solvent
Gasoline with ethanol content (ethyl alcohol or
ethanol)
— Anti-Knock Index is at least 87 AKI
—No more than 15% ethanol
Gasoline with MTBE content
— Anti-Knock Index is at least 87 AKI
—No more than 15% MTBE
Gasoline adapted to the season
Many gasoline fuels are adapted to the seasons.
When the season changes, refueling at high-traf-
fic gas stations is recommended. It is more likely
that the gasoline will be suitable for the season
there.
@) Note
— Gasoline with methanol content that does
not meet the specified conditions may cause >
269

Checking and Filling

corrosion damage and damage to plastic or
rubber components in the fuel system.
— Do not use gasoline that does not meet the
specifications.
— If you are unable to find out if a specific gas-
oline mixture meets the specifications, ask
the gas station operator or their fuel suppli-
er.
— Do not use any gasoline mixture whose
composition cannot be identified.
— Audi does not assume any responsibility for
damage to the fuel system or for perform-
ance problems caused by using gasoline
mixtures different from those specified.
This type of damage also does not fall under
the New Vehicle Limited Warranty or under
the emissions control system warranty.
— If you notice a higher fuel consumption or
poor handling or performance problems due
to such gasoline mixtures, Audi recom-
mends fueling with unblended gasoline.
Gasoline additives
An important issue for many automobile manu-
facturers is combustion residue in the engine
that results from the use of certain fuels.
Although types of gasoline differ depending on
the manufacturer, there are similarities. Certain
substances in the gasoline may cause deposits in
the engine. Additives in the gasoline that should
keep the engine and fuel system clean do not all
function equally.
Audi recommends using TOP TIER Detergent Gas-
oline. For additional information on TOP TIER De-
tergent Gasoline, visit www.toptiergas.com.
If you use incorrect fuels over a long period of
time, the maximum engine performance may be
impaired by combustion residue.
@) Note
— Damage or malfunctions caused by the use
of incorrect types of gasoline are not cov-
ered by the New Vehicle Limited Warranty.
— Only gasoline additives that have been ap-
proved by Audi may be used.
270
Refueling
Messages
A Tank system: malfunction! Please contact
Service
There is a malfunction in the fuel tank system.
Drive to an authorized Audi dealer or authorized
Audi Service Facility immediately to have the
malfunction corrected.
Messages
Applies to: vehicles with plug-in hybrid drive
A Fuel filler door: malfunction! Unlock fuel
filler door manually. See owner's manual
There is a malfunction. You must manually un-
lock the fuel filler door > page 273.
Al Warning! Vehicle performance may be limit-
ed
The fuel tank is almost empty. You must antici-
pate a significant power loss. Refuel immediate-
ly.
& Please refuel and charge battery. Total
range: x mi (km)
or
f& Tank system: please refuel immediately and
charge battery. Total range: x mi (km)
If this indicator light turns on and this message
appears, refuel as soon as possible. Otherwise,
the high-voltage battery is drained > page 131.
AY Fuel filler door open. Please press button
again to refuel
Fueling is possible for a little while after pressing
the G) button. You must press the A button
again if the time limit is exceeded.

4N0012721BF
Checking and Filling

Fueling procedure

RAZ-0013


Fig. 175 Right rear side of the vehicle: opening the fuel
filler door

[RAZ-1124

Fig. 176 Fuel filler door with attached fuel cap
The fuel filler door is unlocked or locked by the
central locking system.
>» Unlock the vehicle if necessary.
> Conventional drive system: Press on the left
side of the fuel filler door to open it > fig. 175.
> Plug-in hybrid drive: Pull on the EV switch in the
driver's door. The fuel filler door will open auto-
matically after venting is complete.
> Unscrew the tank cap counterclockwise.
> Place the cap from above on the open fuel filler
door > fig. 176.
> Plug-in hybrid drive: Note the information for
refueling at the end of this chapter.
> Insert the fuel pump nozzle all the way into the
fuel filler neck.
> Begin fueling. Once the fuel pump nozzle turns
off the first time, the fuel tank is full. Do not
continue fueling, or else the expansion space in
the tank will be filled with fuel.
> After the fuel pump has switched off, wait five
seconds before removing the nozzle to allow

1) Depending on the engine and country

the rest of the fuel to finish dripping into the
fuel tank.
> Turn the fuel cap clockwise until it clicks into
place.
> Close the fuel filler door and then press on the
left side until it latches.
The correct fuel type for your vehicle can be
found ona label located on the inside of the fuel
filler door. For additional information on fuel, see
=> page 269.
For the tank capacity in your vehicle, refer to the
Technical Data > page 344.
To reduce the risk of fuel leaking out or vapors
escaping, make sure that the fuel tank is closed
correctly. Otherwise the ES indicator light will
turn on.

Z\ WARNING
Improper fueling procedures and improper
handling of fuel can lead to explosions, fires,
severe burns, and other injuries.
— Do not smoke. Keep away from open flames.
— The ignition must be switched off when re-
fueling.
— Mobile devices, radio devices, and other ra-
dio equipment should always be switched
off when refueling. Electromagnetic rays
could cause sparks and start a fire.
— If you do not insert the fuel pump nozzle all
the way into the filler tube, then fuel can
leak out. Spilled fuel can ignite and start a
fire.
— Never get into the vehicle when refueling. If
there is an exceptional situation where you
must enter the vehicle, close the door and
touch a metal surface before touching the
fuel pump nozzle again. This will reduce the
risk of electrostatic discharge that can cause
flying sparks. Sparks can start a fire when
refueling.

Z\ WARNING
Audi does not recommend transporting fuel

containers inside the vehicle. Fuel could leak

271

Checking and Filling


out of the container and ignite, especially dur-
ing an accident. This can cause explosions,
fires, and injuries.
— If you must transport fuel in a fuel contain-
er, note the following:
— Always place the fuel container on the
ground before filling. Never fill the fuel
container with fuel while it is inside or on
the vehicle. Electrostatic discharge can oc-
cur while refueling and the fuel vapors
could ignite.
— When using fuel containers made of met-
al, the fuel pump nozzle must always re-
main in contact with the container to re-
duce the risk of static charge.
— Insert the fuel pump nozzle as far as pos-
sible into the filler opening while refuel-
ing.
— Follow the applicable legal regulations in
the country where you are driving when
using, storing and transporting fuel con-
tainers.
— Make sure that the fuel container meets
the industry standards, for example ANSI
or ASTM F852-86.

©) Note
— Remove fuel that has overflowed onto any
vehicle components immediately to reduce
the risk of damage to the vehicle.
— Never drive until the fuel tank is completely
empty. The irregular supply of fuel that re-
sults from that can cause engine misfires.
Uncombusted fuel may enter the exhaust
system and increase the risk of damage to
the catalytic converter.
@) For the sake of the environment
— Do not overfill the fuel tank, or fuel could
leak out when the vehicle is warming up.
— Fuel should never enter the sewer system or
come into contact with the ground.
@) Tips
The fuel filler door on your vehicle does not
lock if you lock the vehicle from the inside us-
ing
the central locking switch.
272
G) Tips
Applies to: vehicles with plug-in hybrid drive
— When inserting the fuel pump nozzle, make
sure that you do not press on the fuel filler
door opener @) with the fuel pump nozzle.
See the label in the fuel filler door @)
> fig. 176. Otherwise, a valve will close in
the fuel filler neck and fueling will stop even
if the tank is not full.
— You must vent the tank system again if you
press on the fuel filler door opener. The fuel
pump nozzle can stay in the fuel filler neck
when doing this. Vent the tank system by
pulling the EQ) switch in the driver's door
again.
— If the engine turned off because the fuel
level was too low, then you may need to re-
fuel with up to 4.0 gallons (15 liters) of fuel
in order for the vehicle to detect the new
fuel level. Otherwise, the engine may not
restart.
— Fuel can age and may lead to problems
when starting. Audi recommends replacing
the fuel in your vehicle within six months.

4N0012721BF
Checking and Filling

Fuel filler door emergency release
Applies to: vehicles with manual fuel filler door release

If the central locking system malfunctions, the
fuel filler door can be unlocked manually.



Fig. 177 Right cover in the luggage compartment: remov-
ing the cover



Fig. 178 Luggage compartment: fuel filler door emergency
release
The emergency opening mechanism is located
behind the right cover in the luggage compart-
ment.
> Remove the screwdriver from the vehicle tool
kit > page 317.
> Carefully insert the flat side of the screwdriver
from below into the center of the top slot in the
cover > fig. 177.
> Use the screwdriver to pull the cover toward the
center of the vehicle and remove the cover.
> To unlock the fuel filler door, loosen the red
loop from the retainer and then pull on the
loop carefully > fig. 178 > ©.
> Press on the left side of the fuel filler door to
open it > page 271, fig. 175.
® Note
Only pull on the loop until you feel resistance.
You
will not hear it release. If you continue to
pull, you could damage the emergency re-
lease mechanism.
@ Tips
Applies to: vehicles with plug-in hybrid drive
— The tank will not be vented if the emergency
release function was used on the fuel filler
door. You can only fill a small amount of
fuel in the tank. Fill only until the fuel pump
nozzle turns off for the first time. Drive to
an authorized Audi dealer or authorized
Audi Service Facility immediately to have
the malfunction corrected.
— Pressure can escape if you open the tank cap
after using the emergency release. This can
create noises.
Emissions control
system
General information
ZA\ WARNING
The temperature of the exhaust system is
high, both when driving and after stopping
the engine.
— Never touch the exhaust tail pipes once they
have
become hot. This could result in burns.
— Do not park your vehicle over flammable
materials such as grass or leaves because
the high temperature of the emissions sys-
tem could start a fire.
— Do not apply underbody protectant in the
exhaust system area, because this increases
the risk of fire.
Catalytic converter
Observe the safety precautions > page 273, Gen-
eral information.


The vehicle may only be driven with unleaded
gasoline, or the catalytic converter will be de-
stroyed.
Never drive until the tank is completely empty.
The irregular supply of fuel that results from that
can cause engine misfires. Uncombusted fuel
could enter the exhaust system, which could >
273

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


— Do not remove the engine cover under any
circumstances. This increases the risk of
burns.
— Due to the risk of electric shock, never touch
the ignition cable or other components in
the electronic high-voltage ignition system
when the engine is running or is starting.
— If a gear is engaged while the vehicle is sta-
tionary and the engine is running, do not
press the accelerator pedal inadvertently.
Pressing the accelerator pedal will cause the
vehicle to move, and this could result in an
accident.
— If inspections or repairs must be performed
while the engine is running, moving compo-
nents (such as the ribbed belt, generator,
and radiator fan) pose an additional risk.
— Set the parking brake first and select the
“P” (Park) selector lever position.
— Always make sure that no parts of the
body, jewelry, ties, loose clothing, and
long hair can be caught in moving engine
components. Before any work, always re-
move any jewelry and/or ties, tie back long
hair, and make sure all clothing fits close
to the body to reduce the risk of anything
becoming caught in engine components.
— Pay attention to the following warnings list-
ed when work on the fuel system or on the
electrical equipment is required.
— Do not smoke.
— Never work near open flames.
— Always have a working fire extinguisher
nearby.
— All work on the battery or electrical system
in your vehicle can result in injuries, chemi-
cal burns, accidents, or burns. Because of
this, all work must be performed only by an
authorized Audi dealer or authorized Audi
Service Facility.
— Limit your exposure to exhaust and chemi-
cals to as short a time as possible.

emit chemicals known to the State of Cali-
fornia to cause cancer and birth defects and
reproductive harm. In addition, certain flu-
ids contained in vehicles and certain prod-
ucts of component wear contain or emit
chemicals known to the State of California
to cause cancer and birth defects or other
reproductive harm.
— 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.



ZA WARNING
California Proposition 65 Warning:
— Engine exhaust, some of its constituents,
and certain vehicle components contain or

@) Note
When filling fluids, be sure not to add any flu-
ids to the wrong reservoirs. Otherwise severe
malfunctions and engine damage will occur.
@) For the sake of the environment
You should regularly check the ground under
your vehicle in order to detect leaks quickly. If
there are visible spots from oil or other fluids,
bring your vehicle to an authorized Audi deal-
er or authorized Audi Service Facility to be
checked.
275

Checking and Filling


Opening and closing the hood
The hood is released from inside the vehicle.



RAZ-0016|


Fig. 180 Unlocked hood: lever
Make sure the wiper arms are not raised up from
the windshield. Otherwise the paint could be
damaged.
Opening the hood
> Applies to: vehicles with plug-in hybrid drive:
Switch the ignition off before releasing the
hood so that the gasoline engine does not start
automatically.
> With the door open, pull the lever <> below
the instrument panel in the direction of the ar-
row > fig. 179.


D_ The & symbol is not available in all countries.
276
>» Raise the hood slightly > page 274.
> Press the lever > fig. 180 in the direction of the
arrow. This releases the hooks.
> Open the hood.
Closing the hood
> Push the hood down until you override the
force of the strut.
> Let the hood fall lightly into the latch. Do not
press it in. > /\.
Messages
B Warning! Hood is not locked. Stop vehicle
and check the lock
The hood latch is not locked correctly. Stop im-
mediately and close the hood.

Z\ WARNING
— 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.
— For safety reasons, the hood must always be
latched securely while driving. Because of
this, always check the hood after closing it
to make sure it is latched correctly. The hood
is latched if the front corners cannot be lift-
ed.
— If you notice that the hood is not latched
while you are driving, stop immediately and
close it, because driving when the hood is
not latched increases the risk of an accident.