cooling AUDI A6 1998 C5 / 2.G AEB ATW Engines Cooling System Components Workshop Manual

19-1


Cooling system components,
removing and installing

WARNING!

The cooling system is pressurized when the
engine is warm. When opening the expansion
tank, wear gloves and other appropriate
protection, cover the cap using a cloth, and
open carefully to relieve system pressure
slowly.

Note:

Cooling system is under pressure when engine
is warm. If necessary reduce pressure before
repair.
Secure all hose connections using production-
type clamps parts catalog.

VAG1921 pliers are recommended for installing
spring clips.
Always replace gaskets, seals and O-rings.
Arrows on coolant lines and hoses must
align.
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19-2


Cooling system components

Coolant hose connection diagram
1 -
Heater core
After replacing, replace coolant
2 -
Lower coolant line Removing and installing Page 19
-22
3 -
Expansion tank
With capPressure relief valve in cap, checking
Page 19
-30

4 -
Oil cooler
Removing and installing Page 17
-7 ,
item 14
5 -
Intake manifold
6 -
Lower coolant hose
7 -
Upper coolant hose
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19-4

Cooling system, draining and filling


Special tools and equipment

VAG1306 drip tray
VAG1274/10 with VAG1274/1 adapter or
VAG1274/8
T40007 refractometer

Draining

Note:
Drain coolant into a clean container for recycling
or reuse.

WARNING!

The cooling system is pressurized when the
engine is warm. When opening the expansion
tank, wear gloves and other appropriate
protection, cover the cap using a cloth, and
open carefully to relieve system pressure
slowly.

- Open coolant expansion tank cap.

- Remove noise insulation panel (arrows).
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19-6


Filling
Note:
CAUTION! - Remove drain plug from coolant pump (arrow).
The cooling system is filled year-round with frost and corrosion
protection additives. Until 6/96, G 011 A8 C coolant (green color) was used.From 7/96 on, only G 012 A8 D coolant (red color) is used.Coolants G 011 A8 C and G 012 A8 D CANNOT be mixed. Mixing
them will cause severe engine damage. Part numbers are for reference only. Always check with your Parts
department for the latest information. If the fluid in the expansion tank is brown, G012 A8 D has been mixed
with other coolant. In this case, flush cooling system and change
coolant. To flush, fill cooling system with clear water and run engine
for approx. 2 minutes. Flushing the system should remove most of the
coolant residue.
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19-7

Note (continued from page Page 19
-6 ):

G 011 A8 C or G 012 A8 D and coolant
additives marked with "according to TL VW
774C" or "according to TL VW 774 D", prevent
frost and corrosion damage as well as calcium
deposits. They also raise the boiling point.
Therefore, cooling system must be filled year-
round with frost and corrosion protection
additives.
A higher boiling point improves engine reliability
under heavy load, particularly in countries with
tropical climates.
Frost protection additives must protect against
frost to about -25 C (-13 F) and to about -35
C (-31 F) in arctic climates.

The coolant concentration must not be reduced
by adding water even in warmer seasons and in
warmer countries. The anti-freeze ratio must be
at least 40%.
If for climatic reasons greater frost protection is
required, the amount of G 011 A8 C or G 012
A8 D can be increased, but only up to 60% to
obtain frost protection to about -40 C (-40 F).
Otherwise frost protection and cooling
effectiveness will be reduced.
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19-8


For coolant G 012 A8 D, use T40007 refractometer to test frost protection
in cooling system.
Recommended mixture ratios:
Vehicles with small cap Frost protection to
Anti-freeze amount
G 012 A8
D
1) Water
1)
-25 C
(-13 F)
-35 C
(-13 F)
40 %

50 % 3.0 ltr.
(3.2 qts.)
3.5 ltr.
(3.7 qts.) 4.0 ltr.
(4.2 qts.)
3.5 ltr.
(3.7 qts.)
1) The quantity of coolant: 7.0 liters (7.4 qts.) can vary depending upon
vehicle options.
- Install lower radiator hose and secure.
- Replace O-ring and install coolant pump drain plug.
Tightening torque: 30 Nm (22 ft lb)

- Screw VAG1274/1 adapter onto coolant expansion tank.
- Attach VAG1274/10 special tool to VAG1274/1 adapter.
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19-10

- Start engine and maintain an engine speed of
about 2000 RPM for approx. 3 minutes.

- Allow engine to idle until the lower radiator hose
is hot.Check coolant level and top up if
necessary. When engine is at normal operating
temperature, coolant level must be at max.
mark; when engine is cold, between min. and
max. marks.

WARNING!

The cooling system is pressurized when the
engine is warm. When opening the expansion
tank, wear gloves and other appropriate
protection, cover the cap using a cloth, and
open carefully to relieve system pressure
slowly.

- Switch engine off.
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19-17

Note:
When installing ribbed belt, check for correct
seating on belt pulley.

- Install V-belt Page 13
-18
.

- Fill up with coolant Page 19
-6 .

WARNING!

The cooling system is pressurized when the
engine is warm. When opening the expansion
tank, wear gloves and other appropriate
protection, cover the cap using a cloth, and
open carefully to relieve system pressure
slowly.

CAUTION!

Be sure the ignition is switched OFF. Failure
to do so may damage the Engine Control
Module (ECM).

- Switch ignition off and reconnect battery Ground
(GND) strap.

- After connecting battery, enter anti-theft code for
radio.

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19-20

Coolant thermostat, removing, installing
and checking


Removing

- Drain coolant Page 19
-4 .

Installing
WARNING!
The cooling system is pressurized when the engine is warm. When
opening the expansion tank, wear gloves and other appropriate
protection, cover the cap using a cloth, and open carefully to relieve
system pressure slowly.
Tightening torque - Remove bolts -4-, remove connector -3-, O-ring -2- and coolant
thermostat -1-.
- Clean and/or smooth O-ring sealing surface.
- Install coolant thermostat.
- Fill up with coolant Page 19
-6 .
Component
Tightening torque
Connector to pump housing 10 Nm (7 ft lb)
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19-23

Installing
Installation is the reverse of removal, noting the
following:

- Fill with coolant Page 19
-6 .

WARNING!

The cooling system is pressurized when the
engine is warm. When opening the expansion
tank, wear gloves and other appropriate
protection, cover the cap using a cloth, and
open carefully to relieve system pressure
slowly.
Pa
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11/18/2002 htt
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yp
e=re
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