2008 AUDI S8 overheating

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Overheating of brakes
To prevent the disc brake of the braked wheel from overheating if
subjected to excessive loads, the EDL cuts out temporarily . The
vehicle remains operational and behaves in the same way as a
vehicle without EDL.
As soon as the brake has cooled down, EDL switches on again auto ­
matically.
& WARNING
• When accelerating on slippery surfaces, such as on ice or snow,
always be careful when depressing the accelerator pedal. Even
with the EDL working, the drive wheels can spin and reduce your ability to control your car. Risk of crash!
• The increased safety afforded by
EDL does not mean that you
can take safety risks. Always adapt your driving style to the road
conditions and traffic situation.
[ i] Tips
If a fault occurs in the ABS, the EDL is also not functioning. This is
indicated by the ABS warning
light => page 21. •
Anti-Slip Regulation System (ASR)
The Anti-Slip Regulation System prevents the driven
wheels from spinning when the car is accelerating.
General notes
The Anti-Slip Regulation System (ASR) is integrated in the electronic
stabili zation program (ESP) . When the vehicle starts up and acceler­
ates, the wheels are prevented from spinning by adjusting the
engine power to match the amount of grip available from the road
surface.
How the system works
ASR performs automatically, i.e. without the driver's intervention.
With the aid of the ABS
sensors=> page 272, ASR monitors the
speed of the driven wheels. If the wheels start to spin, the engine
power is reduced automatically until the tires find enough grip to
lock onto the road surface . The system is active across the entire
speed range.
The ASR works in conjunction with the ABS. If a malfunction should
occur in the ABS, the ASR will also be out of action.
& WARNING
The increased safety afforded by ASR does not mean that you can
take safety risks. Always adapt your driving style to the road
conditions and traffic situation.
[ i] Tips
To ensure that the ASR works properly, all four wheels must be fitted
with identical tires Any differences in rolling radius of the tires can
cause the system to reduce engine power when this is not desired.
See
also=> page 336, "New tires and replacing tires and wheels ".•
Braking
General information
What affects braking efficiency?
Operating conditions and driving habits
The brakes on today's automobiles are still subject to wear,
depending largely on operating conditions and driving
habits=:,& .
On vehicles which are driven mostly in stop-and-go city traffic or
which are driven hard, the brake pads should be checked by your
authorized Audi dealer more often than specified in the
Warranty &
Maintenance booklet. _,,,

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New brake pads
Remember that new brake pads do not have a full braking
effec t during the first 250 miles (400 kilometers) after they
are installed .
New brake pads have to be "burnished in" before they have optimal
grab =>& .
During the break -in period, you s hou ld avoid putting severe loads
on the brakes . Severe loads include, for examp le, sudden hard
braking, in particular at very high speeds or, for example, on moun ­
t ain passes.
& WARNING
N ew brake p ad s don 't h ave the be st stopping po wer and mu st be
"broken -in " during the initial 100 to 150 mile s (150 to 200 kil ome ­
t e rs) of norm al c ity dri ving . You can comp en sa te for thi s by
pr ess ing the brake ped al more firmly . Thi s al so appli es later when
ne w pad s a re in sta lled. •
Catalytic converter
It is very important tha t your emission control sys tem
(catalytic converter) is functioning properly to e nsure that
y o ur vehicle is running in an environmentally sound
manner.
-Always use lead-f ree gasoli ne :=> page 301, "Fuel supply".
-Never run the tank down a ll the way to empty.
-Never put too much motor o il in your engine :=> page 312,
"Adding eng ine oil 'l=;r111
•
-Never try to push -or tow -s ta rt yo ur vehic le.
T he catalytic converter is an efficient "clean -up" device built into the
exhaust system of the vehicle. The catalytic converter burns ma ny
of the po llutants in the exhaust gas before they are released into the
atmosphere.
The exclusive use o f un leaded fue l is critica lly important for the l ife
of the cata lytic converter and proper functioning of the engine.
& WARNING
• Do not park or operate th e veh icle in ar ea s where the hot
e x hau st sys tem m ay come in cont act w ith dr y grass, brush , fuel
s pill or other material which can cau se a fire .
• Do not appl y additi ona l u ndercoating or ru stpr oofing on or
near the exhau st manifol d, exhau st pipe s, ca tal ytic converter or
h ea t shield s. Du ring dri ving , the sub sta nce u sed f or under coating
c ould overhe at and cau se a fir e.
0 Note
• Be aware that just one tank filling with leaded fue l wi ll already
seriously degrade the performance of the catalyt ic converter.
• Do not exceed the correct engine oil
level => page 312 .
• Do not drive until the fuel tank becomes comp letely empty . The
engine cou ld misfire. Unburned fuel could also get into the exhaust
system and this could cause the catalytic converter to overheat .
• Do not turn off t he ignition wh ile the vehicle is moving.
• Do not continue to operate your vehicle under these conditions,
as otherwise fuel can reach the cata lyt ic converter . This cou ld result
in overheating of the converter, requiring its rep lacement .
• To assure eff ic ient operat ion of the Emiss ion Contro l System:
- Have your vehicle maintained properly and in accordance with
the service recommendations in your Warranty
& Maintenance
booklet. _,.

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one half. Never drive faster than the posted speed limit and weather
co nditions permit. •
Reducing unnecessary idling
Even when your car is just idling it burns up fuel.
- Shut the eng ine off when you are not driving the vehicle .
- Do not warm up the vehicle by letting the engine run at
id le .
It makes sense to shut off the engine in traff ic jams, when waiting
for trains to pass at rai lroad crossings, or at traffic lights that have
long waits on red. Turning the engine off for just 30 -40 seconds
saves more fue l than is burned starting the engine again .
It takes a long time for the engine to warm up fu lly when it is
running at idle. However, wear and noxious em issions are espec ially
high when the engine is warming up . So you should drive away as
soon as you start the engine and avoid running at high rpms while
the engine is sti ll warming up.
0 Note
Do not leave engine idling unattended after starting . If warning
lights should come on to indicate improper operation, they would
go unheeded. Extended idling also produces heat, which could
result in overheating or other damage to the vehicle or other
property .•
Regular maintenance
A badly tuned engine unnecessarily wastes a lot of fuel.
- H ave your vehicle serviced at regular intervals .
By having your vehicle regularly serviced by an Audi dealer helps to
ensure t hat it runs properly and economical ly . The condit ion of your
vehic le not only affects its safety and abi lity to hold its va lue, it also
affects
fuel con sumpt ion .
C hec k your oil each time you fill your tan k.
The amount of oil used is related to engine load and speed.
I t is norma l for the oi l consumption of a new engine to reach its
lowest va lue after a certain mileage has been driven.
You must drive your vehicle about 3,000 miles (5,000 kilometers) before you can properly assess oil consumption .
T his also applies to fuel consump tion and engine output .
0 Note
• Have your vehicle maintained properly and in accordance with
t he service recommendat ions in your Warranty
& Maintenance
booklet. Lack of proper ma intenance as well as improper use of the
vehic le wi ll impair the function of the emission control system and
cou ld lead to damage.
• Do not alter or remove any component of the Emission Contro l
System unless approved by the manufacturer.
• Do not alte r or remove any device, such as heat sh ields,
switches, ignition wires, valves, which are designed to protect your
vehic le's Emission Control System and other important vehic le
components .•
Fewer short trips
Fuel consumption will always be relatively high on short
trips.
- Try to avoid driving short dista nces with a cold engine. ~

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&, WARNING (continued)
• When removing the oil drain plug with your fingers, stay as far
away as possible. Always keep your forearm parallel to the ground
to help prevent hot oil from running down your arm.
• Drain the oil into a container designed for this purpose, one
large enough to hold at least the total amount of oil in your engine.
• Engine oil is poisonous. Keep it well out of the reach of children.
• Continuous contact with used engine oil is harmful to your
skin. Always protect your skin by washing oil off thoroughly with
soap and water.
0 Note
Never mix oil additives with your engine oil. These additives can
damage your engine and adversely affect your Audi Lim ited New
Vehicle Warranty.
<£> For the sake of the environment
• Before changing your oil, first make sure you know where you
can properly dispose of the used oil.
• Always dispose of used engine oil properly. Do not dump it on
garden soil , wooded areas , into open streams or down sewage
drains.
• Recycle used engine oil by taking it to a used engine oil collec­
tion facility in your area, or contact a service station. •
Engine cooling system
Coolant
The engine coolant performs two functions: it keeps the
engine from overheating and it protects the engine from
freezing in the winter.
The cooling system is sealed and generally requires little attention.
The cooling system has been filled at the factory with a permanent
coolant which does not need to be changed . The coolant consists of
a mixture of water and the manufacturer's glycol -basedcoolant
additive G12 ++ antifreeze with anti corrosion addi tives (50% for USA
models; 60% for Canadian models). This mixture both assures the
necessary frost protection and protects metal components in the
engine's cooling system from corrosion and scaling. It also raises
the boiling point of the coolant.
Do not reduce the concentration of the coolant in the summer by
adding plain water.
The proportion of coolant additive must be at
least 50% but not more than 60%
to maintain antifree ze protection
and cooling efficiency. If the coolant frost protection is too low, the
coolant could freeze and damage the vehicle heating and engine
cooling system.
For year-round driving, antifreeze is added at the factory for temper­
atures down to :
• -31 °F ( -35 °C) USA
•
-40 °F ( -40 °C) Canada .
You can mix the G12 ++ coolant additive with other additives (G12 +
or G12). Always check with your authori zed Audi dealer .
& WARNING
Before you check anything in the engine compartment, always
read and heed all WARNINGS
~ & in "Working in the engine
compartment" on
page 307.

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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.
.,_
Vehic le care I I Technical data