Compression Check: Testing and Inspection

Compression, Checking

Special tools, testers and auxiliary items required

• Spark Plug Removal Tool (3122 B)

• Compression Tester (V.A.G 1763)

• Ignition Coil Puller (T40039)

Procedure

• Engine oil temperature at least 30 °C.

• Battery voltage at least 12.5 V.

- Remove rear engine cover - top arrows -.





- Remove bolts - arrows -.





- Disconnect the electrical connector on the Engine Coolant Level (ECL) Warning Switch (F66) and lay the coolant reservoir aside with the coolant hoses - 1, 2 and 3 - connected.

- Remove bolts - arrows - and disconnect the electrical connectors to the ignition coils on the left cylinder head.





- Press electrical wiring harness down slightly.

- Disconnect electrical connector - 3 - to the fuel injectors on the rear of the left cylinder head.





• Ignore items - 1, 2 and 4 - and the - arrows -.

- Remove air duct - arrows -.





- Free up the fuel line - 1 - and wire - 2 - to the EVAP canister at the air guide pipe.





- Remove the vacuum hose - 3 - from the connection on the air guide pipe.

- Remove the air guide pipe by loosening the hose clamp - 4 - and opening the clips - arrows -.

- Disconnect vacuum line - 1 -.





- Remove air filter housing and, if applicable, disconnect electrical connector - 2 - on the rear side at the Intake Air Switch-Over Valve (N335).

- Remove bolts - arrows - and disconnect the electrical connectors to the ignition coils on the right cylinder head.





- Press the electrical wiring harness to the side.

- Disconnect the electrical connector - 3 - to the fuel injectors on the rear of the right cylinder head.





• Ignore items - 1, 2 and 4 - and - arrows -.

- Remove all the ignition coils with the Ignition Coil Puller (T40039).





- Remove the spark plugs with Spark Plug Removal Tool (3122 B).

- Check compression pressure using the Compression Tester (V.A.G 1763).

• Using tester => operating instructions.

- Have a second technician press the accelerator pedal down all the way while operating the starter until the pressure increase is no longer displayed on the tester.






Assembling

• Tightening specifications. Refer to => [ Cylinder Head Assembly Overview ] Cylinder Head Assembly Overview.

Assembly is in reverse order of removal, note the following:

• Secure all hose connections with hose clamps appropriate for the model.

- Install the spark plugs.

- Install air filter housing.

- If electrical connectors were disconnected and the engine was started, then malfunctions have been stored in the engine control module. "Generate readiness code" in "Guided Functions" Vehicle Diagnostic, Testing, And Information System (VAS 5051).