1998 AUDI A4 radiator

19-19

Cooling system, draining and filling


Draining

WARNING!

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

- Remove filler cap on coolant expansion tank.

- Remove noise insulation panel.
- Place drip tray VAG 1306 under the engine.

- If bumper has been removed from vehicle, open drain tap -arrow- on
bottom of radiator (left side) by turning anti-clockwise. Fit drain hose on
connection if necessary.
- If bumper has not been removed from vehicle, pull out retaining clip on
bottom hose going from radiator to engine (right side), and pull hose off
radiator.
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19-22

The coolant concentration should not be
reduced by adding plain water, even in warmer
seasons and in warmer countries. The
concentration must be at least 40 %.
If extra antifreeze protection is required in cold
climates, the concentration of G 12 can be
increased, but only up to a maximum of 60 %
(frost protection to about -40 C); if this
concentration is exceeded, the antifreeze
protection will be reduced again and cooling
effectiveness will also be impaired.

Do not reuse the old coolant if the radiator, heat
exchanger, cylinder head or cylinder head
gasket have been replaced.
Recommended mixture ratios:

Frost
protection
to Antifreeze
concentration G
12
1) Water
1)
-25 C
-35 C
40 %
50 % 2.5
ltr.
3.0
ltr. 3.5 ltr.
3.0 ltr.

1) The capacity of the cooling system can vary
depending on the equipment installed on the
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19-23

- Replace O-ring on coolant drain screw and
screw drain screw back into engine.

Tightening torque: 20 Nm

- Install bottom coolant hose and secure.

- Close coolant drain tap on radiator.

- Screw adapter VAG 1274/8 onto expansion tank and insert extension
VAG 1274/10 into the adapter.

- Loosen coolant hose on heat exchanger and pull back hose far enough
so that bleeder hole in hose -arrow- is no longer covered by
connection.
- Fill up coolant until it comes out at bleeder hole in coolant hose.
- Push coolant hose onto connection and tighten.
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19-25

- Start engine and let it idle for about 10
minutes.

- Maintain an engine speed of about 2000 RPM
for about 5 minutes.

- Allow engine to run at idling speed until bottom
hose on radiator becomes hot.

- Check coolant level and top up if necessary.
When engine is at normal operating temperature
coolant level must be on max. mark, and
between min. and max. marks when engine is
cold.

Note:
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.

WARNING!

Hot steam can escape from the expansion
tank when the filler cap is opened. Cover the
filler cap with a cloth and remove it carefully.
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19-26

Radiator, removing and installing


Removing

- Remove front bumper.

Repair Manual, Body Exterior, Repair Group
63


- Drain coolant Page 19
-19
.

- Disengage retaining clips on connecting flanges -arrow- and pull
coolant hoses off radiator.
- Unplug connector from thermoswitch on radiator (bottom left).
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19-27


Vehicles with air conditioner
WARNING!
Do not open the air conditioner refrigerant circuit.
Note:
To prevent damage to the condenser and refrigerant lines and hoses,
ensure that the lines and hoses are not stretched, kinked or bent. - Unbolt pressurizing fan and detach cooling lines for power steering
hydraulic fluid -arrows-.

- Detach air cowls from radiator -4- (left and right).
- Remove securing bolts -1- and -2- for condenser.
- Unplug connector -3- from air conditioner pressure switch -F129.
- Lift condenser up out of its bracket, turn it towards side and secure to
right-hand front wheel with wire.
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19-28


Installing
Install in the opposite order to removing. When installing, note the
following points:
Tightening torques - Release two retaining pins for radiator and pull out upward -arrows-.
- Pivot radiator toward front and lift out.
- Fill with coolant Page 19
-19
.
Component
Nm
Condenser to radiator 10
Cooling lines to radiator 10
Pressurizing fan to radiator 10
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