2018 AUDI A4 radiator cap

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Engine compartment
Working in the engine compartment
Special care is required if you are working in the
engine compartment
F or wo rk in th e en gine c ompar tment , suc h as
ch eckin g and fi llin g flu id s, th ere is a risk of in­
j u ry , sca lding , acci dent s, a nd b urn s. Fo r this
re aso n, follow all the warnin gs and ge nera l
safet y pr eca uti ons pr ov ided in the follow ing in ­
form ation . Th e e ng ine c ompartm en t is a d an­
ger ous a re a .
~ ,&. .
_& WARNING
- T urn the engine off.
- Switch the ign ition off .
- Set the parking brake .
- Shift the gearshift lever to neutral in vehicles with a manual transm ission and se­
lect the P selector lever posit ion in vehicles
with an automatic transmission .
- Let the engine coo l down.
- Never open the hood when there is steam or coolant escaping from the eng ine compart­
ment, because there is a risk that you cou ld
be burned . Wait until no steam or coolant is
escaping.
- Keep children away from the engine com­
partment.
- Never spill flu ids on a hot engine. These flu­
ids (such as the anti-freezing agent con­
tained in the coolant) can ignite.
- Avoid sho rt circu its in the e lectrical system.
- When working in the engine compartment,
remember that the radiator fan can sw itch
on even if the ign ition is switched off , which
increases the risk of inj ury .
- Never open the cap on the coolant expan­
sion tank when the eng ine is warm. The
cooling system is under press ure.
- T o protect your face, hands, and arms from
hot steam or coolant, cover the cap with a
large cloth when opening.
- Do not remove the eng ine cover under any
c ircumstances . This increases the risk of
burns .
Check ing and Filling
-If tests need to be performed with the en­
gine running, there is add itiona l danger due
to mov ing components (such as the ribbed
belt, alternator and radiator fan) and from
the high-voltage ignition system.
-Do not under any circumstances activate the
throttle inadvertently (for example, by hand
from the engine compartment) if the veh i­
cle is stat ionary but the eng ine is running
and a gea r is engaged. Otherwise, the veh i­
cle will start to move immed iate ly and this
could result in an accident.
- Pay attent ion to the following warn ings
when wor k on the fue l system is required :
- Do not smoke.
- Never work near open flames.
-Always have a working fi re 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
o nly by an
author iz ed Audi dealer or author iz ed Audi
Serv ice Facility.
-To reduce the r isk of electric shock and in­
jury, never touch the following components
when the engine is runn ing or is being start­
ed:
- Ign ition cable
- Other components in the e lectronic high-
vo ltage ign ition system
-I f you must check or perform wo rk on the
engine wh ile it is running:
-First, set the parking brake and and move
the gearshift lever to neutral (for manual
transm issions) or select the P selector lev­
er position (for automatic transm iss ions).
- Always proceed w ith extreme caution so
that clothing, jewelry or long hair do not become caught in the radiator fan, fan
belt or other moving components or do
not come into contact with hot compo­
nents. Tie bac k long hair befo re beginning
work and do not wear clothing that can hang down into the engine.
-Lim it your exposure to exhaust and chemi­
cals to as short a time as possible
¢ .&. .
32 3

areas, into open streams or down sewage
drains.
- Recycle used engine oil by taking it to a used
engine oil collection facility in your area, or
contact a service stat ion .
Cooling system
Coolant
The engine coo ling system is filled with a mixture
of purified water and coolant additive at the fac­
tory. This coolant must not be not changed.
The coolant level is monitored through
the. in­
dicator light
¢ page 30. However , we do recom­
mend occasiona lly checking the coolant level
manually.
If you must add coolant, use a mixture of water
and coolant addit ive. Mixing the coolant additive
with distilled water is recommended.
Coolant additive
The coolant additive is made of anti -freezing and
corrosion protection agents. Only use the fol low­
ing coolant additives . These additives may be
mixed with each other.
Coolant additive Specification
G13
TL 774 J
G12++ TL
774 G
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 coolant can freeze
and damage the engine.
Coolant Freeze protec-
additive tion
Warm min . 40% min. -13 °F
regions max .
45% (
- 25 °()
Cold min.
50% max
. -40 °F
regions max.
55% (-40 °()
(D Note
-
Before the start of winter, have an author­
ized Audi dealer or authorized Audi Service
Facility check if the coolant additive in your
Checking and Filling
vehicle matches the percentage appropriate
for the climate. This is especia lly important
when driving in colder climates.
- If the appropriate coo lant additive is not
available in an emergency, do not add any
other additive. You could damage the en­
gine. If this happens, only use water and re­
store the correct mixture ratio with the
specified coolant add itive as soon as poss i­
ble .
- Only refill w ith new coolant.
- Radiator sealant must not be mixed with
the coolant.
Adding coolant
Fig. 270 E ngine compartment: re lease button on coolant
expansion tank
Observe the safety precautions ¢,&. in Working
in the engine compartment on page 323.
Checking the engine coolant level
.. Park the vehicle on a level surface .
.. Switch the ignition off .
.. Read the coolant level on the coolant expansion
tank
¢ fig. 270.
.. The coolant level must be between the MIN and
MAX markings when the engine in co ld. When
the engine is warm it can be slightly above the
MAX marking.
Adding coolant
.. Let the eng ine cool down .
.. Place a cloth over the coolant expansion tank
cap .
.. Push the release button ¢ fig. 2 70 and carefu l­
ly unscrew the cap to the left until you feel re-
sistance¢ ,A. IIJ,-
329

Checking and Filling
.,. Push the release button again and remove the
cap comp lete ly .
.,. Make sure that the fluid level rema ins stable.
Add more coolant if necessary .
.,. Turn the cap to the right to secure it until you
feel resistance a second t ime.
Coolant loss usually indicates there is a leak . Im ­
mediately drive your vehicle to an authorized
Audi dealer or authorized Audi Serv ice Facility
and have the cooling system inspected . If the
coo ling system is not leaking, a loss can come
from the coolant boiling through overheating
and being pushed out of the cool ing system.
_& WARNING
- T he coo ling system is under pressure. Do
not open the coolant expansion tank cap
when the engine is hot. This increases the
risk of burns.
- The coo lant add itive and the coolant can be
dangerous to your healt h. For this reason,
keep the coolant in the origina l container
and away from children. There is a risk of poison ing.
- When working in the engine compartment, remember that the radiator fan can switch
on even if the ign ition is switc hed off, which
increases the risk of in jury.
(D Note
Do not add coolant if the expansion tank is
empty. There may be air in the cooling sys­
tem, wh ic h increases the risk of engine dam­
age.
If th is is the case, do not continue dr iv­
ing . See an a uthorized Aud i dea le r or author­
ized Aud i Service Fa cil ity fo r assistance.
330
Brake fluid
Fig. 271 En gine compa rtment: cap o n brake fluid reservo ir
Observe the safety precautions¢.&, in Working
in the engine compartment on page 32 3 .
Check ing the brake fluid level
.,. Read the brake fluid level on the brake fluid
reservoir ¢ page 325, fig . 268 . The brake flu id
level must be between the MI N and MAX ma rk­
ings ¢.&, .
The brake f lu id level is monito red automatically.
Changing the brake fluid
Have the brake fluid changed regularly by an au­
thorized Audi dea ler or authorized Audi Service
Facility.
_& WARNING -
- If the brake flu id leve l is below the MIN
marking, it ca n impair the brak ing effect
and driving safety, wh ich increase the r isk of
an accident. Do not continue dr iv ing . See an
author ized Audi dealer or au thori zed Audi
Serv ice Facility fo r ass ist ance.
- I f the brake fl uid is old, b ubbles may form
in the bra ke system dur ing heavy bra king.
This wo uld im pair b raking per formance and
driving safety, which increases the risk of an
accident.
- To ensure the brake system functions cor­
rectly, only use bra ke fluids tha t comp ly
wit h VW standard 50 1 14 or
FMVSS- 116 DOT 4 .
(D Note
-If the bra ke f lu id leve l is ab ove the MAX
marking, bra ke fluid may le ak o ut over the

Checking and Filling
Charging the vehicle battery
Fig. 272 Engine co mpa rtment : connec tors for a c harger
and jump start cab le s
Req uirement: only use chargers with a m aximum
c hargi ng vo lta ge of 30 amp s/14.8 Volt s.
The
vehicle battery cables remain connected .
.,. Read the warnings c> .&. in General warnings
about batteries on page 331
and c> ,&. .
.,. Switch off the ignition and all electrical equip ­
ment .
.,. Open the hood 9 page 324 .
.,. Open the red cover on the positive terminal
c>fig. 272 .
.,. Clamp the charger terminal clamps to the jump
s ta rt pin s
according to the instruct ions . (pin
under the red cover = "positive ", p in with hex­
agonal head= "negative ") .
.,. Inse rt the powe r cable for the charg ing device
i nto the socke t and switch the dev ice on .
.,. At the end of the charging process , switch the
charger off and pull the power cab le out of the
socket .
.,. Remove the charger terminal clamps.
.,. Close the red cover on the positive terminal.
.,. Close the hood c> page 324 .
A WARNING
-A highly explosive mixtu re of gases can form
when cha rging batter ies. On ly charge the
vehicle batte ry in well-ven tilated areas.
- A drai ned vehicle battery can freeze at tem­
peratu res a round 32
QF (0 QC). A froze n or
thawed veh icle bat tery must not be charged
and must not be used anymore. The ba ttery
housing can crac k and battery acid can leak
o ut if ice forms, wh ich increases the r isk of
an exp losion and chemical burns. Contact an
332
author ized Audi dealer or authorized A udi
Service Facility for more information.
- Do not connect or disconnect the charging
cable whi le charging because this increases
the risk of an explos ion.
@ Tips
- Only charge the vehicle battery t hrough the
connect ions in the engine compartme nt.
- Read all of the manufacturer's instructions
for the charger before charging the vehicle
battery.
Windshield washer system
Fi g. 2 7 3 Engine compar tm ent: washer flui d res ervoir cap
The windshield washer fluid reservoir¢ contains
t he cleaning solution for the windshield and th e
headlight washer system *
c> page 325, fig. 268 .
The reservoir capaci ty can be found in
c> page 381.
To reduce the risk of lime scale deposits on the
spray no zzles, use clean water with low amounts
of calcium . Always add w indow 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 .
(D Note
-The concentration o f ant i-freez ing agent
must be adjusted to the ve hicle operat ing
conditions in the respective climate . A con­
cent ration t hat is too high can lead to vehi­
cl e damage.
- Never add radiator anti-freeze or other addi­
t ives to the washer fluid.