coolant AUDI A4 1998 B5 / 1.G AWM Engine Cooling System Components Workshop Manual

19-1


Cooling system components,
removing and installing

WARNING!

Hot steam can escape when opening the cap
on the expansion tank: Cover the cap with a
cloth and open carefully.

Note:

When the engine is warm the cooling system is
under pressure. If necessary release pressure
before beginning repair work.
Secure all hose connections with the correct
hose clips (same as original equipment):

Parts Catalog

Hose clip pliers VAG 1921 are recommended
when installing spring type clips.
Replace all gaskets and seals.
The arrow markings on the coolant lines and on
the ends of the hoses must be aligned with
each other.
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19-2


Cooling system diagram

1 -
Radiator
Removing and installing Page 19
-26
After replacing, fill with fresh coolant
2 -
Upper coolant line
3 -
Thermostat Removing and installing coolant pump
Page 19
-12

Checking Page 19
-22
4 -
Coolant pump
Removing and installing Page 19
-12
Check for ease of movement
5 -
Turbocharger
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19-3


6 -
Cylinder head/cylinder block
After replacing, fill with fresh coolant
7 -
Heating system heat exchanger After replacing, fill with fresh coolant
8 -
Lower coolant line Removing and installing Page 19
-23
9 -
Oil cooler
Removing and installing Item 23 ,
Page 17
-10

10 -
Expansion tank
With filler capTesting pressure relief valve in filler cap
Page 19
-33

11 -
Intake manifold
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19-5

Draining

Note:
Catch drained off coolant in a clean container for
re-use or disposal.

WARNING!

Hot steam can escape when opening the cap
on the expansion tank: Cover the cap with a
cloth and open carefully.

- Open cover of coolant expansion tank

- Remove sound insulation -arrows-.
- Place drip tray VAG 1306 below engine.

- Remove lower coolant hose retaining clip -arrow- and remove coolant
hose from radiator.
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19-6

Note:

With bumper and air duct in front of charge air cooler removed, the
coolant can also be drained from the radiator via the drain screw -arrow-.
If necessary use an auxiliary hose.

- Disconnect lower coolant hose on oil cooler -arrow-, and drain off
remaining coolant.
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19-7

Filling

Note:

The cooling system is filled all year round with a
mixture of water and an antifreeze/corrosion
protection agent.
Only use coolant additive G 012 A8 D meeting
specification TL VW 774 D. Identification color:
red

CAUTION!

G 012 A8 D and other coolant additives
cannot be mixed. Otherwise, serious damage
to the engine may result.
If the fluid in the expansion tank is brown, this
means G 012 A8 D has been mixed with
another type of coolant. In this case, flush out
the cooling system and fill with fresh coolant. To
flush the system, fill it with clean water and run
the engine for about 2 minutes. This should
remove as much of the old coolant as possible.
G 012 A8 D and coolant additives marked
"meeting specification TL VW 774 D" prevent
frost and corrosion damage and stop scaling
while at the same time raising the boiling point
of the coolant. For these reasons the cooling
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19-8

Because of its high boiling point, the coolant
improves engine reliability under heavy loads,
particularly in countries with tropical climates.
Protection against frost must be assured to
about -25 C (in arctic climatic countries to
about -35 C).

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 greater frost protection is required in very cold
climates, the amount of G 012 A8 D can be
increased, but only up to 60% (this gives frost
protection to about -40 C). Otherwise, frost
protection is reduced again and cooling
effectiveness is also reduced.

Only use clean drinking water for mixing the
coolant.
If radiator, heat exchanger, cylinder head or
cylinder head gasket is replaced, do not reuse
old coolant.
Use special tool T10007 to check frost
protection of coolant additive G012 A8 D in
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19-9

Recommended mixture ratios:

Frost
protection
to
Anti-freeze
concentration
G
012A8
D 1)
Water
1)
-25 C
-35 C
40%
50% 3.0 l
3.5 l 4.0 l
3.5 l

1) Coolant quantity: 7.0 liters (may vary
depending upon the vehicle equipment)

- Install lower coolant hose and secure.

Note:
To fill expansion tank without special tools, remove expansion tank and
temporarily raise it about 100 mm. - Screw adapter VAG 1274/8 onto coolant expansion tank.
- Fit special tool VAG 1274/10 onto adapter.
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19-10


- Remove seal from plenum chamber cover in direction of arrow.
- Remove plenum chamber cover -1- from front.
- Push back protective cover for coolant hose at connection of heat
exchanger.

- Release coolant hose to heat exchanger and pull back hose until
bleeder hole in coolant hose -arrow- is no longer covered by
connection.
- Top up coolant until it flows out at bleeder hole in coolant hose.
- Push coolant hose on connection and tighten.
- Install expansion tank cap.
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19-11

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

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

WARNING!

Hot steam can escape when opening the cap
on the expansion tank: Cover cap with a cloth
and open carefully.

- Check coolant level and top up if necessary. If
engine is warm, coolant level must be at max.
mark; if cold, between min. and max. marks.

- Stop engine.
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