AUDI A4 1997 B5 / 1.G APB Engine Cooling System Components

19-20


Note:
Observe disposal regulations for coolant.
Filling
Notes: - Drain coolant from engine at drain screw -arrow-.
Use only coolant additive G 12 - meeting specification VW 774 D.
Identification: colored red. G 12 must not be mixed with any other additives. If the fluid in the expansion tank is brown, this is an indication that G
12 has been mixed with another type of coolant. In this case the
coolant must be changed.
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19-21

G 12 and coolant additives complying with
specification "VW 774 D" prevent frost and
corrosion damage, scaling and also raise the
boiling point of the coolant. For this reason the
system must be filled all year round with the
correct additive for frost and corrosion
protection.
Particularly in countries with tropical climates,
the higher boiling point of the coolant improves
engine reliability when working under heavy
load.
The system must be protected against frost to
about -25 C (in arctic climates to about -35
C).

Use special tool T40007 to test coolant concentration and antifreeze
protection.
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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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vehicle.
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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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19-24


- Loosen bleeder screw on rear coolant line -arrow- below expansion
tank.
- Fill up coolant until it comes out at bleeder screw.
- Screw in bleeder screw (20 Nm).

- Loosen bleeder screw on front coolant line -arrow- between power
steering pump and left cylinder head.
- Fill with coolant until it comes out at bleeder screw.
- Screw in bleeder screw (20 Nm).
- Fill coolant up to max. mark.
- Close filler cap on expansion tank.
- Set heater controls to maximum heat setting.
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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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