cooling AUDI S8 2008 User Guide

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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

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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. .,,

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Rain sensor ........ .... .... .... ... 80
Service position . ....... .... .... ... 82
Washer reservoir ...... .. .... .... . 323
Winter driving Windows . .... .... .... ... .... .... 292
Winter operation Battery . ... .. .... .... .... .. . .. .. . 318
Cooling system ...... .... .... ... . 314
Steering wheel heating .. .... . .... . 1 19
Tires .. ......... .... .... ... .... . 273
W. t t
' in er ires . .. .. .... .... ... .... ... .
Al l-whee l drive . ...... .... ... .... .
Wiper blades 341
341
See Windshield wipers ............. 82
X
Xenon-Lights ...... .... .... ......... 362
y
Yellow symbols ... .... .... .... .... ... 34
Controls and equip­
ment Safety first Vehicle operation
Vehicle care Do-it-yourself service Technical data