2008 AUDI S8 check engine light

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Checking and filling
Engine hood
Releasing the engine hood
The engine hood is released from inside the vehicle.
Fig. 259 Driver's side
footwell: engine hood
release lever
-Pull the release lever on the left under the instrument
panel ~ fig. 259 in the direct ion of the arrow.
The hood pops up slight ly under spring pressure. •
Opening the engine hood
Fig. 260 Release lever
under the engine hood
Before opening the engine hood, make sure that the wind­
shie ld wipers are flat against the windshield. Otherwise,
they could damage the paint on the hood.
Li ft the hood
slightly~ &.
-Pull up on the release under the hood:=} fig. 260. Thi s
releases the catch.
-Open the hood all the way.
The hood is kept in the open position by two gas struts.
& WARNING
Hot engine coolant can burn you.
• To reduce the risk of being burned , never open the hood if you
see or hear steam or coolant escaping from the engine compart­
ment . Wait until no steam or coolant can be seen or heard before
carefully opening the hood . •

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& WARNING
B efor e you che ck an ything in the eng ine comp artm ent, a lw ays
read and heed all WARN ING S
~ & in "W orkin g in the engin e
c omp artment " on
page 30 7. •
Appl ies to vehicles: with 12- cy linder engine
Engine compartment overview : 1 2-cyl inder
engine
These are the most important items that you can check.
F ig . 262 Ty pi cal layout for c ontain ers, en gine oil dip st ic k a nd e ngine o il filler
ca p
G) Windshield/head light washer container ( Q ) . . . . . . . . 323
@ Brake fluid reservoir ( ) . . . . . . . . . . . . . . . . . . . . . . . . 317
© Engine oi l dipstick (orange) . . . . . . . . . . . . . . . . . . . . . . 311
© Engine oil filler cap ('t=:11) .. ...... .... ... ... ... .. . .
© Coolant expansion tank (- L l ..................... .
& WARNING
Before you check anything in th e engine co mpartment , alway s
read and he ed all W ARNI NGS
~ & in "Wo rking in t he engin e
c ompartm ent " on
page 307.
[ i ] Tip s
The coolant expansion tank is located under a cover .•
Engine oil
Engine oil specifications
312
315
The engine oil us ed in your Audi needs the right kind of
oil.
The engine in your Audi is a sophisticated powerplant that was built
to exacting specifications. This engine needs the right kind of engine oil that meets specifications regarding quality and viscosity
so that it can run smoothly and re liably. Choosing the righ t oil and
changing oil within the time and mileage interva ls printed in your
vehicle's Warranty
& Ma intenance book let matters a lo t more today
than it did years ago. Audi has developed a special quality standard
for engine oil that wil l help assure that your vehicle's engine wi ll get
the lubrication it needs for proper operation .
Mode rn engine lubrication has taken a quantum leap in the last few
years . Many syn thetic oils available today provide better engine
lubrication that can outlast traditional petroleum-based oils,
making them a smart choice for use throughout the life of your Audi.
Whether you use synthetic or petroleum -based engine oil, the oi l
that you use must conform to Audi's oi l qua lity standard VW 502 00
..,
Vehic le care I I irechnical data

Checkin g and fillin g 1111
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•
the form of Service or Repair Ord ers that all scheduled maintenance
was perfo rmed in a t imely man ner. •
Engine oil consumption
The engin e in your vehicle d ep ends on an adequate
amount of oil to lubricate and cool all of its moving parts.
In order to provide effect ive lubrication and cool ing of internal
engine components, all internal combustion engines consume a
certain amount of o il. Oil consumption varies from engine to eng ine
and may change significantly over the life of the engine . Typically,
eng ines wi th a specif ied break -in period
(see => page 2771 consume
more oil during the break -in period than they consume after oi l
consumption has stabi lized .
Under normal conditions, the rate of oil consumption depends on
the quality and viscosity of the oil, the RPM (revolutions per minute)
at which the engine is operated, the ambient temperature and road
conditions. Further factors are the amount of oil dilution from water
co ndensation or fue l residue and the oxidation level of the o il. As
any engine is subject to wear as mileage builds up, the oil consump ­
t io n may increase over time until rep lacement of worn components
may become necessary .
With all these variables coming into play, no standard rate of oil consu mption can be estab lished or specified. T here is no a lternative
to regular and frequent checking of the oil level, see
Note .
If the yellow eng ine o il level warni ng symbol in the instrume nt
cluster ~ lights up, you should check the oil level as soon as
poss ible
with the oil dipstick => page 311 . Top off the oil at your
earliest
convenience=> page 312.
& WARNING
Bef ore you che ck anything in the eng ine comp artment , alw ay s
read and heed all WARNINGS
=> & in "Working in the engine
c ompartment " on
page 307 .
0 Note
Driving with an insuff ic ie n t o il level is l ikely to cause severe damage
to the engine.
[ i ] Tip s
• The oil pr es sure warning displ ay level . Do not rely on it. Instead , check the oil level in your engine at
regular inter vals, preferably ea ch time you refuel , and al ways before
going on a long trip.
• I f you have the impression your engine consumes excessive
amounts of oi l, we reco mmend that you consult your Audi dealer to
have the cause of your concern properly diagnosed . Keep in mind
t hat t he acc urate measureme nt of oil consump tion requ ires g reat
care and may take some time. Your Audi dealer has instructions
about how t o measure oil consumpt ion accurately. •
Checking the engine oil level
Vehicle care
Fig. 26 3 Illu stration of
prin cipl e 1: Mar ker s on
o il dip sti ck ...

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0 Note
• Before winter sets in, have the coolant checked to see if the
coolant additive in your vehicle is sufficient to meet the climate
conditions. This is especially important if you live in a region where
the winter is extremely cold. If necessary , increase the proportion of
coolant additive to 60%.
• When adding coolant additive to your cooling system,
remember:
-We recommend using only coolant additive G12+ + (check the
label) for your vehicle. This coolant additive is available at autho­
rized Audi dealers. Other types of antifreeze can significantly
reduce corrosion protection . The resulting corrosion can cause a
loss of coolant and serious engine damage .
• Do not add any type of radiator leak sealant to your vehicle's
engine coolant. Adding radiator repair fluid may adversely affect the
function and performance of your cooling system and could result
in damage not covered by your New Vehicle Limited Warranty .•
Checking the engine coolant level
The engine coolant level can be checked with a quick
glance.
Fig . 267 Engine
compartment : Coolant
expansion tank
Before you check anything in the engine compartment,
always read and heed all WARNINGS => & in "Working in
the engine compartment" on
page 307.
Turn off the ignition.
Read the engine coolant level from the coolant expan­
sion
tank => fig. 267 . With a cold engine, the coolant level
should be between the "min" and "max" markings. When
the engine is warm, the level may be slightly above the
"max" marking.
The location of the coolant expansion tank can be seen in the
engine compartment illustration =>
page 308.
To obtain an accurate reading, the engine must be switched off.
The expansion tank in your vehicle is equipped with an electric
coolant level sensor.
When the coolant level is too low, the warning light in the Auto­
Check
System => page 31 will blink until you add coolant and the
level has been restored to normal. Even though there is an electric
coolant level sensor, we still recommend you check the coolant level
from time to time.
Coolant loss
Coolant loss may indicate a leak in the cooling system. In the event
of coolant loss, the cooling system should be inspected immedi­
ately by your authorized Audi dealer . It is not enough merely to add
coolant .
In a
sealed system, losses can occur only if the boiling point of the
coolant is exceeded as a result of overheating.
& WARNING
The cooling system is under pressure and can get very hot. Reduce
the risk of scalding from hot coolant by following these steps.
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Vehic le care I I Technical data

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&, WARNING (continued)
• Turn off the engine and allow it to cool down.
• Protect your face, hands and arms from escaping fluid and
steam by covering the cap with a large, thick rag.
• Turn the cap slowly and very carefully
in a counter-clockwise
direction while applying light, downward pressure on the top of
the cap.
• To avoid being burned, do not spill antifreeze or coolant on the
exhaust system or hot engine parts. Under certain conditions, the
ethylene glycol in engine coolant can catch fire.
0 Note
Do not add any type of radiator leak sealant to your vehicle's engine
coo lant. Adding radiator repair fluid may adversely affect the func­
tion and perfo rmance of your cooling system and could result in
damage not covered by your New Vehicle Limited Warranty .
[ i] Tips
On vehicles with the 12-cylinder engine, the expansion tank is
located under a cover. •
Adding coolant
Be very careful when adding engine coolant.
Before you check anything in the engine compartment,
always read and heed all WARNINGS => & in "Wor king in
the engine compartment" on
page 307.
-Turn off the engine.
-Let the engine cool down.
-Place a thick rag over the coolant expansion tank
=> page 315, fig. 267 and carefully twist the cap counter­
clockwise
=> & .
-Add coolant.
-Twist the cap on again tightly.
Replacement engine coolant must conform to exact specifications
=> page 314, "Coolant". Even in an emergency, if coolant additive
G12++, G12+ or G12 is not available, do
not use a different additive.
Use plain water instead until you can get the correct additive and
can restore the correct ratio. This should be done as soon as
possible.
If you have lost a considerable amount of coolant, then you should
add cold antifreeze and cold water only when the engine is cold.
Always use
new engine coolant when refilling.
Do not fill coolant above the "MAX" mark. Excess coolant will be
forced out through the pressure relief valve in the cap when the
engine becomes hot.
& WARNING
• The cooling system is under pressure and can get very hot.
Reduce the risk of scalding from hot coolant by following these
steps.
-Turn off the engine and allow it to cool down.
- Protect your face, hands and arms from escaping fluid and
steam by covering the cap with a large, thick rag.
- Turn the cap slowly and very carefully
in a counter-clockwise
direction while applying light, downward pressure on the top
of the cap.
- To avoid being burned, do not spill antifreeze or coolant on
the exhaust system or hot engine parts. Under certain condi-
tions, the ethylene glycol in engine coolant can catch fire. .,,

Checking and filling -_______________________________ =..:..:..::...::.:..;~:.....:...;_.:..:..,__--=--.J
fl::. WARNING (continued )
• Antifr eez e is po isonous. Always stor e antifreeze in it s origin al
c ontainer and well out of the re ach of ch ildren .
• If you drain the coolant , it must be caught and saf ely stored in
a prop er co ntainer cle arly m arked "poi son ".
0 Note
• Coolant po llutes the environment and cou ld cause an engine
fire. Excess coolant will be forced out through the pressure relief
valve in the cap when the engine becomes hot.
• I f, in an emergency, only wa ter can be added, the correct ratio
between water and
antifreeze => page 314 must be restored as soon
as possib le .
W For the sake of the environment
Drained coolant should not be reused . A lways dispose of used
coolant while observing all environmental regulations . •
Radiator fan
The radiator fan switches on automatically by i tself .
The radiator fan is driven by the engine via the V-be lt. The viscous
clutch regulates the speed of the fan according to the temperature
of the coo lan t.
An auxiliary electric radiator fan * switches on and off depending on
coolant temperature and other vehic le opera ting condi tions.
After you switch the engine off , the auxiliary fan can continue
running for up to 10 minutes -even with the ignition off. It can even
switch on again later by
itself =>& , if
• the temperature of the engine coo lant rises due to the heat
bu ild -up fro m the engine in the engine c ompar tment , or •
the engine compartment heats up because the vehicle is parked
in intense sunlight .
& WARNING
• To reduce the ri sk of per sonal injury never tou ch the radiator
fan .
• The au xiliary elect ric fan i s te mperature controlled and can
switch on suddenly e ven when the engine is not running .
• The au xiliary radiato r fan switche s on auto matically when th e
eng ine coolant reache s a certain temperature and will continue to
run until the coo lant temperat ure drop s. •
Brake fluid
Checking brake fluid level
T he brake fluid level can be checked with a quick glance.
-w ;:;
Fig . 26 8 Engin e
c o mp artm ent: B ra ke
fluid r eservoir
Before you check anyth ing in the e ngine compartmen t,
always read and heed all WARNINGS ~ & in "Working in
t h e engi ne compartment " on
page 307. _,,,
Vehicle care I I irechnical data

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-Read the brake fluid level from the brake fluid reservoir
=> fig. 268. The brake fluid level must be between the
"MIN" and "MAX" markings.
The brake fluid reservoir is located at the rear partition of the engine
compartment on the left
side~ page 308.
The fluid level may drop slightly after some time due to the auto­
matic adjustment of the brake pads. This is not cause for alarm.
If the brake fluid level falls considerably below the "MIN" mark, the
brake warning/indicator light (U.S. models:
BRAKE , Canadian models:
«D>l will come on~ page 22 and~ page 30. Do not continue to
operate the vehicle. The complete brake system should be thor­
oughly checked by an authorized Audi dealer or other qualified
facility and the cause corrected. If the brake fluid level is too low, the
brake warning/indicator light will illuminate. Contact an authorized
Audi dealer
immediately. •
Changing brake fluid
Have the brake fluid changed by an experienced techni­
cian.
Brake fluid absorbs moisture from the air. If the water content in the
brake fluid is too high, corrosion in the brake system may result
after a period of time. The boiling point of the brake fluid will also
decrease considerably and decrease braking performance.
Therefore, the brake fluid must be changed
every two years. Always
use new brake fluid which conforms to Federal Motor Vehicle Stan­
dard "FMVSS 116 DOT 4".
The brake fluid reservoir can be difficult to reach, therefore, we
recommend that you have the brake fluid changed by your autho­
rized
Audi dealer. Your dealer has the correct tools, the right brake
fluid and the know-how to do this for you.
& WARNING
• Brake fluid is poisonous . It must be stored only in the closed
original container out of the reach of children!
• Brake failure can result from old or inappropriate brake fluid .
Observe these precautions:
-Use only brake fluid that meets SAE specification J 1703 and
conforms to Federal Motor Vehicle Standard 116. Always check
with your authorized Audi dealer to make sure you are using
the correct brake fluid. The correct type of brake fluid is also indicated on the brake fluid reservoir .
- The brake fluid must be new. Heavy use of the brakes can
cause a vapor lock if the brake fluid is left in the system too
long. This can seriously affect the efficiency of the brakes as
well as your safety . This could result in an accident .
0 Note
Brake fluid will damage the paint of your vehicle .
<£> For the sake of the environment
Because of the problem of proper disposal of brake fluid as well as
the special tools required and the necessary expertise, we recom ­
mend that you have the brake fluid changed by your authorized Audi
dealer. •
Battery
General information
Under normal operating conditions, the battery in your Audi does
not need any maintenance. With high outside temperatures or long
daily drives we recommend that you have the electrolyte level .,,_

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checked by a service facility. The e lectrolyte level should also be
checked each time the battery is charged =>
page 321.
Have the battery checked when you take your vehicle in for service.
You are well advised to replace a battery that is older than 5 years.
With ce rtain types of airbag deployment, the battery is discon­
nected from the vehicle electrical system for safety reasons=>
& in
"Repair, care and disposal of the airbags" on
page 232.
Di sconn ecting the b atte ry terminal s
Some veh ic le functions (power window regulators, for example) are
lost if the battery terminals are disconnected. These functions have
to be relearned after the battery terminals are connected again. To
prevent this, the battery should only be disconnected from the
veh icle electrical sys tem when absolu tely necessary for repairs.
Veh icl es not driv en for lo ng p eriods
If you do not drive your vehicle over a period of several days or
weeks, electrical components are gradually cut back or switched off.
This reduces energy consumpt ion and maintains starting capability
over a longer period
=> page 274 .
Be aware that when you unlock your vehicle, some of the conve ­
nience functions may not operate, such as the Advanced Key*, the
remote control or the power seat adjustment. The convenience
functions will be ava ilable again when you turn on the ignition and
start the engine.
W int er operati on
During the winter months, battery capacity tends to decrease as
temperatures drop. This is because more power is also consumed
while starting, and the headlights, rear window defogger, etc. , are
used more often .
Avoid unnecessary power consumption, particularly in city traffic or
when trave ling only short distances . Let your authorized Audi dea ler
check the capacity of the vehicle battery before winter sets in
=> page 321. A well charged battery will n ot only prevent starting
problems when the weather is cold, but wi ll also last longer.
[ i ] Tips
If your vehic le is left standing for severa l weeks at extreme ly low
temperatures, the vehicle battery should be removed and stored
where it will not freeze. Th is wil l prevent it from be ing damaged and
having to be replaced.•
Working on the battery
Be espe cially careful when w orking on or near the battery.
Fig . 2 69 Lugg age
co mpartment : R ight ­
si de sto ra ge c omp art­
m ent
F ig. 2 70 Lugg age
co mp artment : B atte ry
T h e ba tter y is lo ca te d in t he luggage compartm ent on the
r ight side b ehind a c ove r. Before you check a nything in the
luggag e co m partment,
read and heed all WARNINGS =>& . .,.
Vehic le care I I irechnical data