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".