2008 AUDI A5 engine overheat

Towing a trailer 208Towing a trailerDriving the vehicle with a trailer or
caravanTechnical requirements
The towing bracket must comply with certain technical
requirements.Your car is intended mainly for transporting passengers and
luggage. However, if suitably equipped, it can also be used to tow a
trailer or caravan.
If the car is supplied with a factory-fitted towing bracket it will
already have the necessary technical modifications and meet the
statutory requirements.
A 13-pin socket is provided to make the electrical connection
between the car and the trailer. If the trailer has a 7-pin plug you can
use an adapter cable. This is available from Audi dealers.
WARNING
If a towing bracket is retrofitted, the installation should be carried
out by a qualified workshop.•
In particular in high outside temperatures it is not possible to
drive up long steep gradients without a suitable cooling system.
The engine would then overheat.
•
Incorrect installation can result in a safety risk.
Points to check before towingTrailer weights
Never exceed the maximum permitted trailer weights ⇒page 295.If you do not load the trailer up to the maximum permitted trailer
weight, you can then climb correspondingly steeper gradients.
The maximum trailer weights listed are only applicable for altitudes
up to 1000 m above sea level. With increasing altitude the engine
power and therefore the car's climbing ability are impaired because
of the reduced air density, so the maximum trailer weight has to be
reduced accordingly. The weight of the car and trailer must be
reduced by 10% for every further 1000 m (or part thereof). This
figure refers to the combined weight of the (loaded) vehicle and
(loaded) trailer.
The figures for the draw bar weight that appear on the identification
plate of the towing bracket are for certification purposes only. The
correct figures for your specific vehicle, which may be lower than
these figures for the towing bracket, are given in the registration
documents. Also refer to ⇒page 295.
Distributing the load
Distribute loads in the trailer so that heavy objects are as near to the
axle as possible. Loads carried in the trailer must be secured to
prevent them slipping.
Where possible, operate the trailer with the maximum permitted
draw bar weight on the ball joint of the towing bracket, but do not
exceed the specified limit.
Tyre pressure
Check the tyre pressures on your car and adjust for “full load” condi-
tions (refer to the sticker listing the tyre pressures on the end face
of the driver's door). It may also be necessary to adjust the tyre pres-
sures on the trailer according to the recommendations of the trailer
manufacturer.
Exterior mirrors
Check whether you can see enough of the road behind the trailer
with the standard mirrors. If this is not the case you should have
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Towing a trailer 210•
In low outside temperatures, both the towing vehicle and the
trailer should be fitted with winter tyres.
WARNING
It is essential that you adjust your speed to suit the weather, road
and traffic conditions. Do not let the trailer stabilisation system
tempt you into taking any risks when driving – this can cause acci-
dents.•
The ESP and trailer stabilisation system cannot defy the laws
of physics. This should be kept in mind, particularly on slippery
and wet roads and when towing a trailer with a light load.
•
The trailer stabilisation system is functional, regardless of
whether the trailer has a mechanical overrun brake or not.
•
The trailer stabilisation system is not always able to detect
swaying of trailers with a light load and will therefore not inter-
vene.
•
A trailer can still “jack-knife” on slippery roads with little grip,
even if the towing vehicle is equipped with the trailer stabilisation
system.
•
Trailers with a high centre of gravity may even tip over before
they start to sway sideways.
•
If you are not towing a trailer, but the trailer socket is being
used (e.g. for an illuminated bicycle rack), the trailer stabilisation
system may be activated in extreme driving conditions.
•
Please note the additional information and warnings
⇒page 210.
Notes on towing
Driving with a trailer always requires extra care.Weight distribution
Try to avoid towing a loaded trailer with an unladen vehicle. If this
cannot be avoided, drive extra slowly to allow for the unbalanced
weight distribution.
Speed
The stability of the car and trailer is reduced with increasing speed.
For this reason it is advisable not to drive at the maximum permis-
sible top speed in unfavourable road, weather or wind conditions.
This applies especially on a downhill gradient.
You should always reduce speed immediately if the trailer shows
the slightest sign of swaying. Never try to stop the swaying by accel-
erating further.
Always brake in good time. If the trailer has an overrun brake, apply
the brakes gently at first and then firmly. This will prevent the jerking
that can be caused by the trailer wheels locking. Change down in
good time before going down a steep hill so that you can use the
engine braking effect to slow down the vehicle.
Swaying and pitching can be reduced by stabiliser aids. We recom-
mend having stabiliser aids installed when towing trailers with a
high trailer weight. They can be purchased and installed at an Audi
dealer.
Overheating
When climbing long hills in hot weather with the engine running
fast in low gear, you should keep an eye on the coolant temperature
gauge ⇒page 11. Reduce speed immediately if the needle moves to
the top end of the scale. If the temperature warning lamp
 in the
instrument cluster should start flashing, stop the car and let the
engine cool down by running it at idling speed for a few minutes.
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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.
•
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 checked 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 not 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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