Compression pressure, checking

WARNING: This page is about a different car, the 2006 Audi A4, 2005 Audi A4, 2004 Audi A4, 2003 Audi A4, and 2002 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

Special tools and equipment

Fig 1: Identifying Spark Plug Wrench 3122 B

Courtesy of VOLKSWAGEN UNITED STATES, INC.

3122B Spark plug removal tool

Fig 2: Compression Tester VAG1381 Or VAG1763

Courtesy of VOLKSWAGEN UNITED STATES, INC.

VAG1381 or VAG1763 Compression tester

Requirements

Minimum engine oil temperature: 30°C
Battery voltage at least 12.7 V

Work sequence

Fig 3: Removing Rear Engine Cover

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Remove rear engine cover (arrows).

Fig 4: Removing Cover In Engine Compartment (Left Side)

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Remove cover -1- in engine compartment (left side).

Fig 5: Removing Coolant Hoses

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Remove coolant reservoir (arrow)
Disconnect electrical wiring to Engine Coolant Level (ECL) warning switch -F66- at bottom of expansion tank.
Tie coolant expansion tank with connected coolant hoses -1 to 3- to side.

Fig 6: Removing Cover In Engine Compartment (Right Side)

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Remove cover -1- in engine compartment (right side).

Fig 7: Evaporative Emission Canister Purge Regulator Valve N80 And Air Duct

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Remove bolts (arrows).
Detach Evaporative Emission (EVAP) canister purge regulator valve -N80- -1- at air guide.
Remove air guide -2-.

Fig 8: Removing Air Filter Housing

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Remove air filter housing (arrows).
Disconnect electrical harness connector -1- at Mass Air Flow (MAF) sensor.
Remove air guide hose -2- together with Mass Air Flow (MAF) sensor.

Fig 9: Removing Bolts At Left Cylinder Head Cover & Disconnecting Electrical Harness Connectors

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Remove bolts -4- and -5- at left cylinder head cover.
Disconnect electrical harness connectors -1- to -3- and -6-.
Remove ignition coils (arrows).

Fig 10: Removing Bolts At Right Cylinder Head Cover & Disconnecting Electrical Harness Connectors

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Remove bolts -5- and -6- at right cylinder head cover.
Disconnect electrical harness connectors -1- to -4-.
Remove ignition coils (arrows).
Using 3122B spark plug removal tool, remove spark plugs.

Remove all harness connectors to injectors.
Open throttle fully.
Test engine compression using VAG1381 or VAG1763 compression tester.

NOTE: Using VAG1381 or VAG1763 Compression Tester:

Refer to Operating instructions

Activate starter until no further pressure increases are indicated by VAG1381 or VAG1763 compression tester.

Compression values

New Bar gauge pressure	Wear limit Bar gauge pressure	Difference between cylinders bar Gauge pressure
10.0 to 14.0	9.0	max. 3.0

Install spark plugs and ignition coils.

The following work step must be performed after the engine compression test.

Check DTC and erasing if necessary.

Use VAS5051 tester.

Tightening torque

Component	Nm
Spark plugs into cylinder head	30