engine overheat AUDI RS5 CABRIOLET 2013 User Guide

214 Checking and filling
Engine cooling system
Coolant
The engine coolant performs two functions: it
keeps the engine from overheating and it pro ­
tects the engine from freezing in the winter .
The cooling system is sealed and generally re­
quires little attention .
The cooling system has been filled at the fac­ tory with a permanent coolant which does not need to be changed. The coolant consists of a
mixture of water and the manufacturer's gly ­
col-basedcoolant additive G13 antifreeze with
anticorrosion add itives (50% for USA models;
60% for Canadian models). This mixtu re 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 cool­
ant in the summer by adding plain water .
The
proportion of coolant additive must be at
least 50% but not more than 60%
to main­
tain antifreeze protection and cooling efficien­
cy. If the coolant frost protection is too low,
the coolant could freeze and damage the vehi­
cle heating and eng ine cooling system .
For year-round driving, antifreeze is added at
the factory for temperatures down to:
- -31 ° F ( - 3 S °C) USA
- -40 °F ( - 40 °C) Canada .
_&. WARNING
Before you check anything in the engine
compartment, always read and heed all
WARNINGS ~
A in Working in the engine
compartment on page 207.
(D Note
- Before winter sets in, have the coolant
checked to see if the coolant additive in
your vehicle is sufficient to meet the cli­
mate conditions . This is especially impor­
tant if you live in a region where the win­
ter is extremely cold. If necessary, in- crease the
proportion of coolant additive
to 60%.
- When adding coolant additive to your
cooling system, remember:
- We recommend using on ly coolant ad­
ditive G12++ or G13 for your vehicle.
This coolant additive is availab le at au­
thor ized Audi dealers. Other types of
antifreeze can significantly reduce cor­
rosion protection. The resulting corro­
sion cah cause a loss of coolant and se­
rious engine damage.
- Do not add any type of rad iator leak seal­
ant to your vehicle's engine coolant .
Adding radiator repair fluid may adverse­
ly affect the function and performance of
your cooling system and could result in
damage not covered by your New Veh icle
Limited Warranty.
· Checking the engine coolant level and
adding coolant
Be very careful when adding engine coolant.
Fig. 180 E n g in e compart men t: Cover on the coo la nt
expansio n tan k
Fig. 181 En g in e compart men t: markings in the coo la n t
expansion tank
ll>

Before you check anything in the engine com­
partment,
al ways r ead and heed all W ARN­
ING S ¢ A in Working in the engine compart­
ment on page 207.
The "MIN" und "MAX" markings are found on
the bi-level disc in the interior of the coolant
expansion tank
¢ fig . 181.
.,. Park your vehi cle on a level sur face.
.,. Turn off the ignition .
.,. Let the engine coo l down .
.,. Place a thick rag over the coolant expansion
tank and
c a refully turn the cap counter ­
clockwise ¢
.&,.
.,. Read the engin e coolant le vel inside the
coolant expans ion tank ¢
fig. 180,
¢ page 209, fig . 177. With a cold engine,
the coolant leve l should be between the
" M IN" and "MAX" mark ings
¢ fig. 181
-arrows- . When the eng ine is warm, the lev­
el may be slightly above the "MAX" marking.
.,. The MAX marking may be covered with a
maximum of 1 mm of coolant when yo u
fill
coolant .
.,. Twist the cap on again tightly.
The location of the coolant expansion tank
can be seen in the engine compartment illus­
tration
¢ page 209.
To obtain an accurate read ing, the engine
must be switched off .
The expans ion tank in you r vehicle is equipped
with an electric coolant level sensor .
When the coo lant level is too low, the warning
light in the A uto-Check System¢
page 18 wi ll
b lin k until you add coo lant and the level has
been restored to norma l. Even though there is
an electric coolant level sensor, we sti ll rec­
ommend you check the coolant leve l from
time to time.
Coolant loss
Coolant loss may indicate a leak in the coo ling
system . In the event of coolant loss, the cool ­
i n g system should be inspected immediately
by your authorized Audi dealer. It is not
enough merely to add coolant.
Checkin g and fillin g 215
In a sealed system, losses can occur on ly if
the boiling point of the coolant is exceeded as
a resu lt of overheating.
Adding coolant
Rep lacement engine coolant must confo rm to
exact specificat ions¢
page 214, Coolant .
We recommend using only coo lant add itive
Gl2++, Gl3 or i n an emergency Gl 2+ . Do not
use a different add itive. In an emergen cy use
plain water until you can ge t the correct addi­
tive and can restore the correct ra tio. This
sho uld be done as soon as possib le .
If you have lost a cons iderab le amount o f
coolant, then you sho uld add cold ant ifreeze
and co ld water on ly when the engine is cold.
A lways use
new engine coo la nt when refilling.
Do not fill coolant above the "MAX" mark. Ex­
cess coolant will be fo rced out through the
pressure relief valve in the cap when the en­
gine becomes hot.
_& WARNING
- Th e cooling system is un der pressure and
can get very hot. Reduce the risk of
scalding from hot coolant by following
these ste ps.
- Turn off the engine and allow it to coo l
down.
- Protect your face, hands and arms from
escaping fluid and steam by covering
the cap w ith a large, th ic k rag.
- Turn the cap s lowly and very carefully
i n a counter-clockwise direction while
applying light, downward pressure on
the top of the cap.
- To avoid being bu rned, do not spill an­
tifree ze or coolant o n the ex haust sys­
tem o r hot engine p arts. Under ce rtain
con ditio ns, the ethy lene glycol in en­
gine coolant can catch fire.
- Antifreeze i s poisonous. Always s tore an­
tifreeze in its original container an d well
out of the reach of children .
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