ECU AUDI A6 1999 C5 / 2.G AHA ATQ 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 with a cloth and
open carefully to relieve system pressure
slowly.

Notes:

Hoses are secured with spring-type clips. If
servicing, only use the same type of spring-type
clip.

Parts catalog

VAG1921 pliers are recommended when
installing spring-type clips.
The O-rings installed at the quick-release
connections must be replaced if damaged or
leaking.
Seals and gaskets must always be replaced.
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19-2


Cooling system components (on body)

1 -
Radiator
Removing and installing page 19
-17
After replacing, completely replace coolantWith ATF cooler on vehicles with automatic
transmission
2 -
Securing clip
3 -
Securing rubber
4 -
O-ring Replace if damaged
5 -
Lower coolant hose Secured to radiator with retaining clipMake sure hose is securely seatedCoolant hose connection diagram page 19
-9
6 -
Securing clip
To secure temperature switch in coolant
hose
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19-3


7 -
O-ring
Replace if damaged
8 -
Coolant Fan Control (FC) thermal switch -
F18- 35 Nm (26 ft lb)For electric coolant fan
Switching temperatures, stage 1:On: 92-97 C (198-207 F)Off: 84-91 C (183-196 F)
Switching temperatures, stage 2:
On: 99-105 C (210-221 F)Off: 91-98 C (196-208 F)
9 -
Locking bolt
10 -
10 Nm (7 ft lb)
11 -
Fan ring
Clipped into air ducting and secured with
locking 9 bolt
12 -
2-pin harness connector
13 -
Coolant fan -V7- Checking page 19
-26
14 -
Rubber washer
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19-4


16 -
Upper coolant hose
Secured to radiator with retaining clipMake sure hose is securely seatedCoolant hose connection diagram page 19
-9
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19-5


Cooling system components (on engine)

1 -
Connection
For thermostat
2 -
O-ring Always replace
3 -
Coolant thermostat Removing and installing page 19
-23
Note installation position page 19
-23
Checking:
Heat thermostat in waterOpening begins at approx. 86 C (187 F)Min. opening: 7 mm (0.28 in.)
4 -
Bleeder screw 20 Nm (15 ft lb)
5 -
Bolt 25 Nm (18 ft lb)
6 -
Retaining clip Make sure clip is seated securely
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19-7


14 -
O-ring
Replace if damaged
15 -
Expansion tank Check using VAG1274 cooling system
tester with VAG1274/9 adapter
16 -
Upper coolant hose Secured to radiator with retaining clipMake sure hose is securely seatedCoolant hose connection diagram page 19
-9
17 -
Coolant line
Coolant hose connection diagram page 19
-9
18 -
Rear toothed belt guard
19 -
Gasket
Always replace
20 -
Coolant pump Check for ease of movementCompletely replace if damaged or leakingRemoving and installing page 19
-20
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19-14

- Replace coolant drain plug O-ring and install
coolant drain plug into engine.

Tightening torque: 20 Nm (15 ft lb).

- Install lower right coolant hose and secure with
retaining clip.

- Secure coolant drain valve to radiator.

- Screw VAG1274/9 onto expansion tank and insert VAG1274/10 into
adapter.

- Loosen clamp on coolant hose on heater core and pull back hose until
bleeder hole in coolant hose (arrow) is no longer sealed by connection.
- Top off coolant until it flows out from bleeder hole in coolant hose.
- Push coolant hose onto connection and tighten.
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