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 min. 30 C.
- Battery voltage min. 12.5 V.
- Switch off ignition.
- For vehicles with auxiliary heater, remove bolts - arrows - for exhaust pipe of parking heater/auxiliary heater on noise insulation.
- Loosen quick-release fasteners - 1 - and remove front noise insulation.
- Disconnect electrical connector on Engine Speed (RPM) Sensor G28 - arrow - at bottom of transmission.
- Remove front engine cover - 1 - and rear - 2 - - arrows -.
- Remove left air duct hose - arrows -.
- Remove oil dipstick - 2 - from guide tube.
- Remove bolts - 1 - and - 3 -.
- Disconnect electrical connectors to ignition coils and press wiring harness to side.
- Disconnect vacuum hose - 2 - from air guide hose.
- Loosen hose clamps - arrows - and lay aside air guide hose.
CAUTION:
Hose connectors - 1
- must not be opened.
- Remove bolts - 1 - and - 2 -.
- Disconnect electrical connectors to ignition coils and press wiring harness to side.
- Remove all ignition coils using Ignition Coil Puller T40039.
- Using spark plug removal tool 3122 B , remove spark plugs.
- Check compression using compression tester V.A.G 1763.
NOTE:
- Using tester → operating instructions.
- Have a second technician press accelerator pedal completely and at the same time operate starter long enough until pressure increase no longer appears on tester.
| Compression pressure | Bar pressure |
|---|---|
| New | 10.0 to 14.0 |
| Wear limit | 9.0 |
| Difference between cylinders | max. 3.0 |
Assembly is in reverse order of removal, note the following:
- Install spark plugs → 28 - IGNITION/GLOW PLUG SYSTEM .
- As a final step, check Engine Control Module (ECM) DTC memory and erase it, since malfunctions were stored by disconnecting electrical connectors
Tightening specifications
| Component | Nm |
|---|---|
| Wiring for ignition coils at cylinder head cover | 5 |