engine overheat AUDI A5 COUPE 2008 User Guide

Checking and topping up fluids
236otherwise this would reduce the antifreeze protection. In addition,
the cooling effect will be adversely affected.
Vehicles for export to countries with a cold climate (such as Sweden,
Norway and Finland) are supplied with antifreeze protection down
to about -35 °C. The concentration of the antifreeze additive for
these countries should always be at least 50%.
Caution
•
It is advisable to have the cooling system checked before the
winter season to make sure that the antifreeze concentration is
adequate for the conditions to be expected. This applies particularly
if you intend to take the car into a colder climate zone. If necessary,
have the anti-freeze concentration increased to 50 - 60% as required.
•
Use only anti-freeze additive G12+, an additive meeting the spec-
ification “TL-VW 774 F ”. Other additives may give considerably infe-
rior corrosion protection. The resulting corrosion in the cooling
system can lead to a loss of coolant, causing serious damage to the
engine.
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The coolant additive G12+ can be mixed only with additives G11
and G12.
Checking coolant level
The coolant level can be checked at a glance.
– Switch off the ignition.
– Read off coolant level on radiator expansion tank ⇒fig. 227. When the engine is cold it should be between
the “MIN” and “MAX” marks. When the engine is hot it
may be slightly above the “MAX” mark.The coolant level should be checke d with the engine switched off.
The coolant level is monitored by a warning lamp in the instrument
cluster ⇒page 32 . However, we recommend that it should be
checked occasionally.
Coolant losses
Any loss of coolant normally indicates a leak in the cooling system.
In this case the cooling system should be inspected by a qualified
workshop without delay. It is no t sufficient merely to top up the
coolant.
If there are no leaks in the system, a loss of coolant can only occur
if the coolant boils and is forced out of the system as a result of
overheating.
Caution
Radiator sealants must not be added to the coolant. Such additives
could seriously impair the function of the cooling system.Topping up the coolant
Be careful when topping up coolant.– Switch off the engine.
– Wait for the engine to cool down.
– Cover the cap on the expansion tank ⇒fig. 227 with a
cloth, and carefully unscrew the cap anti-clockwise
⇒ .
Fig. 227 Engine
compartment: Mark-
ings on radiator expan-
sion tank
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