1998 AUDI A6 engine

21-18

Special tool VAG 1687, connecting to
pressure adapter VAG 1687/1 (2.7L BiTurbo)
For illustrations purposes VAG is shown lying in
the engine compartment. In practice the tool
should be hung from the hood.

- Connect VAG 1687 quickly to prevent smoke
from leaking out.

VAG 1687 is shown connected to VAG 1687/1 -black arrow-
Shop air supply will be connected to VAG 1687 -at white arrow-
- Perform pressure test Page 21
-19
.
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21-19

Performing pressure test:

- With outlet hose -1- of VAG 1687 connected to air pressure adapter:
- Attach shop air supply line to previously installed male fitting ( Page
21
-14
.

CAUTION! - Open valve -3- between regulator valve and gauge.
- Adjust test pressure up to 0.5 bar ( CAUTION below) by turning
regulator valve -2-.
DO NOT pressurize the system above 0.5 bar!Doing so may force oil into the intake system which can damage
the engine.
- Slowly open outlet valve -4- (after gauge) to test hose connections.
- Observe pressure gauge for a drop in pressure.
Pa
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21-31

- Remove intake air duct between cowl and air
cleaner housing.

- Remove air cleaner housing cover.

- Remove the following lines/harness connectors:
1 - At wastegate bypass regulator valve -N75-
2 - At Evaporative Emissions (EVAP) purge regulator valve -N80-
3 - At power output stage -N122-
4 - At Mass Air Flow (MAF) sensor -G70-
- Remove hose connections and remove air cleaner housing (arrows).
- Remove engine covers.

- Unbolt crankcase ventilation hose -1- at cylinder head cover and heat
shield.
- Unbolt both oil supply line bolts -3-.
- Remove heat shield -4-.
- Remove sleeve -2- from coolant return hose.
Pa
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11/18/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
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21-33

Note:
Add oil to turbocharger through oil supply line
connection flange.

- Fill up coolant Page 19
-4 .

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.

Note:
After installing the turbocharger, let engine idle
for approx. 1 minute without increasing engine
speed. This ensures adequate oil supply to the
turbocharger.

- Check engine oil level Page 17
-27
.
Pa
ge 45 of 50 Turbochar
ger s
ystem
11/18/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE02.21.1