engine overheat AUDI S4 SEDAN 2013 User Guide

222 Check ing 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 G 13 antifreeze with
anticorrosion add itives (SO% for USA mode ls;
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
a lso raises the boiling point of the coolant .
Do not reduce the concentration of the coo l­
ant in the summer by adding plain water .
The
p ro po rti on of c ool ant add it iv e mu st b e at
lea st 50 % but not mo re th an 60%
to main­
tain antifree ze protection and cooling efficien­
cy. If the coolant frost protect ion is too low,
the coolant could freeze and damage the veh i­
cle heating and eng ine cooling system .
For year-round driving, antifreeze is added at
the factory for temperatures down to:
- -31° F(-3S°C)USA
- - 40 ° F ( - 40 °C) Canada.
_& WARNING
Before yo u check anything in the engine
compartment, always read and heed all
WARNINGS
¢ &. in Working in the engine
compartment on page 215.
(]) Note
-
- Before winter sets in, have the coolant
checked to see if the coo lant additive in
your vehicle is s uffic ient to meet the cli­
mate cond it ions . Th is is especially impor­
tant if you live in a region where the w in­
ter is extremely cold . If necessary, in- crease the p
roportion of coo lant additive
to 60%.
- When adding coolant additive to your
cooling system, remember:
- We recommend us ing on ly coolant ad­
d itive G12++ or G13 for your veh icle .
This coolant additive is availab le at au­
thor ized Audi dealers. Other types of
ant ifreeze can s ignificantly reduce cor­
rosion pro tection. The resulting cor ro­
sion can cause a loss o f coolant and se ­
rious engine damage.
- Do not add any type of rad iator leak seal­
ant to yo ur vehicle's engine coolant .
Adding radiator repair fl uid may adverse ­
ly affect the function and performance of
your cooling system and cou ld resu lt in
damage not covered by your New Veh icle
Limited Warranty.
' Checking the engine coolant level
The engine coolant level can be checked with
a quick glance.
F ig. 170 En gin e compa rtm en t: Cover o n the coo la n t
expans io n ta nk
-"' -"' >< .,
"'
.. Before yo u check anything in the engine
compartment,
alwa ys read and heed all
W ARNINGS ¢ .&. in Working in the engine
compartment on page 215 .
.,. Park your vehicle o n a level surface .
.,. Tu rn off the ignition .
.. Read t he engine coolant level from the
coo la nt expansion tank ¢
fig. 170 ,
r=:> page 217, fig . 167. With a cold engine,
the coolant leve l should be between the
"MIN" and "MAX" markings . When the en­
gine is warm, the level may be slightly above
the "MAX" marking.
IJII,

The location of the coolant expansion tank
can be seen in the engine compartment illus­
tration
q page 217 .
To obtain an accurate read ing , the eng ine
must be switched off .
The expa nsion tank in you r vehicle is equipped
with an elec tric coolant level sensor.
When the coolant level is too low, the warning
light in the Auto-Check System
q page 18 wi ll
b lin k until you add coo lant and the level has
been restored to norma l. Even t hough the re is
an e lec tric coolant level sensor, we s till rec ­
ommend you check the coolant leve l from
time to time .
Coolant loss
Coolant loss may indi cate a leak in the coo ling
sys tem. In the event of coolant loss, the cool­
ing system should be inspected immedia tely
by your authorized A udi dealer. It is not
enough merely to add coolant.
I n a
s ealed system, losses can occur only if
the boiling point of the coolant is exceeded as
a result of overheating.
A WARNING
The cooling system is unde r press ure and
can get ve ry hot. Reduce the risk of sca ld­
ing from hot coolant by following these
steps.
- Turn off the engine and allow it to coo l
down.
- Protect yo ur face, hands and arms from
escaping fluid and steam by covering the
cap with a large, thick rag.
- Turn the cap slowly and very carefu lly in
a counter-clockwise direction wh ile ap­
plying light, downward pressure on the
t op of the cap .
- To avoid being bu rned, do not spill ant i­
freeze or coo lant on the exhaust system
o r hot eng ine parts . Unde r certai n condi­
t ions, the ethy lene g lycol in engine cool­
an t ca n catc h fire.
Checkin g and fillin g 223
@ Note
Do not ad d any type of radiator leak sea l­
ant to your ve hicle's engine coolant. Add ­
i ng radiator repa ir flui d may adverse ly af­
fect the funct ion and performance of your
cooling system and could result in damage not cove red by your New Vehicle l imi ted
Warranty .
Adding coolant
Be very careful when adding engine coolant.
Before you check anyth ing in the eng ine com ­
partment,
always read and heed all WARN­
INGS q & in Working in the engine compart ­
ment on page
215 .
.,. Turn off the engine.
.,. let the engi ne cool down.
.,. Place a thick rag over the coolant expansion
tank
q page 222, fig . 170 and carefully turn
the cap counter-clockwise
q &_ .
.,. Add coo la nt.
.,. Twist the cap o n aga in
tightly.
Rep lacement engine coo lant must confo rm to
exact spec ificat ions
q page 222, Coolant. We
recommend using on ly coo lant additive G 12+
+ , G 13 or in an eme rgency G12+. Do
not use a
different additive. In an emergency use pla in
water until you can get the correct additive
and can restore the correct ratio . This sho uld
be done as soon as possible.
If you have los t a cons iderab le amount o f
coolant , then you sho uld add cold antifreeze
and co ld water on ly when the engine is cold.
A lw ays use
new engine coo lant w hen refilling.
Do not f ill coo lant above t he "MAX" mark. Ex­
cess coola nt w ill be fo rced o ut through t he
pressure relief valve in the cap when the en­
gine becomes hot.
A WARNING
- The cooling system is under pressure and
can get very hot. Reduce the risk of ..,.
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