Compression Check: Testing and Inspection

Compression, Checking

• If ceramic sheathed element glow plugs are installed, check the idle stabilization control before removing the glow plugs vehicle diagnosis, testing and information system (VAS 5051B). Only if one or more cylinder(s) is/are noticeable at this point is the compression test warranted.

Special tools, testers and auxiliary items required

• Flex wrench (3220)

• Torque wrench (V.A.G 1331)

• Adapter (V.A.G 1381/12)

• Compression tester (V.A.G 1763)

Test Conditions

• Engine oil temperature min. 30° C

Test Sequence

- Disconnect the central connector for the pump injector unit.

• If ceramic sheathed element glow plugs are installed, always follow the information for removing and installing them => [ Ceramic Glow Plugs ] Ceramic Glow Plugs.

- Remove all glow plugs or ceramic glow plugs using flex wrench (3220).

- Install the adapter (V.A.G 1381/12) in place of the glow plugs or ceramic glow plugs.





- Check compression pressure using compression tester (V.A.G 1763).

• Using tester => operating instructions.

- Operate starter until tester shows no further pressure increase.

Compression pressure:

New: 25 to 31 bar pressure, Wear limit: 19 bar positive pressure.

Permissible difference between all cylinders: 5 bar.

• If ceramic sheathed element glow plugs are installed, always follow the information for removing and installing them => [ Glow Plug Identification ] Application and ID.

- Install the glow plugs or the ceramic glow plugs using the flex wrench (3220).

Tightening specifications: 15 Nm.

- Check the engine control module fault memory => [ Engine Control Module DTC Memory, Checking and Erasing ] Engine Control Module DTC Memory, Checking and Erasing.

• By disconnecting the central connection for the pump injector unit, DTCs will be stored. Query the fault memory and erase, if necessary.