coolant AUDI A4 1999 B5 / 1.G APB Engine Cooling System Components

19-1


Cooling system components,
removing and installing

WARNING!

Hot steam can escape from the expansion
tank when the filler cap is opened. Cover the
filler cap with a cloth and unscrew it carefully.

Notes:

When the engine is hot the cooling system is
under pressure. Carefully open filler cap on
expansion tank to release pressure before
starting repair work.
Hoses are secured with spring-type clips. When
repairing only use spring-type clips.
VAG 1921 pliers are recommended when
installing spring-type clips.
The O-rings fitted at the quick-release
connections must be replaceed if damaged or
leaking.
When installing coolant hoses, ensure that they
are free of stress and do not come into contact
with other components (observe markings on
coolant connection and hose).
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19-2

Cooling system components (on body),
removing and installing


Notes:

Parts of cooling system on engine Page 19
-
8 .

Diagram of coolant hose connections Page 19
-17
.

Draining and filling with coolant Page 19
-
19
.

Coolant mixture ratios Page 19
-19
, draining
and filling cooling system.
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19-3


1 -
Radiator
Removing and installing Page 19
-26
After replacing, replace coolant in complete
system
2 -
Securing clip
3 -
Securing rubber
4 -
O-ring Replace if damaged
5 -
Bottom coolant hose Secured to radiator with retaining clipCheck for secure seatingDiagram of coolant hose connections
Page 19
-17

6 -
Rubber washer
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19-5


13 -
Radiator fan thermoswitch (-F18-), 35 Nm
For electric fan
Switching temperatures: Stage 1on: 92...97 Coff: 84...91 C
Switching temperatures: Stage 2
on: 99...105 Coff: 91...98 C
14 -
Seal
Always replace
15 -
Drain screw Tightening torque: 10 Nm
16 -
Top coolant hose Secured to radiator with retaining clipCheck for secure seatingDiagram of coolant hose connections
Page 19
-17

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19-6


17 -
Bolt
Tightening torque: 5 Nm
18 -
Mounting rod
19 -
Guard plate
20 -
Bolt Tightening torque: 5 Nm
21 -
Bolt Tightening torque: 5 Nm
22 -
Radiator Removing and installing Page 19
-26
After replacing, replace coolant in complete
system
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19-9


5 -
Filler cap
Test with cooling system tester VAG 1274
and adapter VAG 1274/9 Test pressure 1.4...1.6 bar
6 -
O-ring Replace if damaged
7 -
Bolt Tightening torque: 10 Nm
8 -
Expansion tank Carry out leak test of cooling system with
cooling system tester VAG 1274 and
adapter VAG 1274/8
9 -
To rear water line Diagram of coolant hose connections
Page 19
-17

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19-10


10 -
Top coolant hose
Secured to radiator with retaining clipCheck for secure seatingDiagram of coolant hose connections
Page 19
-17

11 -
Coolant line
Diagram of coolant hose connections
Page 19
-17

12 -
Rear toothed belt guard
13 -
Gasket
Always replace
14 -
Coolant pump Check that pump runs freelyIf damaged or leaking replace completeRemoving and installing Page 19
-29
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19-11


15 -
To front coolant line
Diagram of coolant hose connections
Page 19
-17

16 -
Bolt
Tightening torque: 10 Nm
17 -
Bolt Tightening torque: 25 Nm
18 -
Lower coolant line Diagram of coolant hose connections
Page 19
-17

19 -
Oil cooler
20 -
Bolt
Tightening torque: 25 Nm
21 -
Bolt Tightening torque: 10 Nm
22 -
Belt pulley For viscous fan
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19-12


23 -
Bolt
Tightening torque: 10 Nm
24 -
Fan wheel for viscous fan
25 -
Viscous fan coupling Note left-hand threadTightening torque only applicable when
using open-end spanner 3312 Tighten to 37 Nm
26 -
Bolt Tightening torque: 25 Nm
27 -
Bracket For viscous fan
28 -
From bottom of radiator Diagram of coolant hose connections
Page 19
-17

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19-13


Cooling system components (on engine,
rear), removing and installing

1 -
To front water hose
2 -
Front coolant line
Diagram of coolant hose connections
Page 19
-17

3 -
Bleeder screw
Tightening torque: 20 Nm
4 -
Coolant hose From auxiliary water pump to front coolant
line
5 -
Auxiliary water pump
6 -
Coolant hose From rear coolant line to auxiliary water
pump
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