Attention. Diesel engines require a high pressure compression tester, up to approx. 40 bar.
The pressure difference between the individual cylinders must not exceed 3.0 bar (in diesel engine 5.0 bar). If the pressure difference in one or more cylinders in relation to the rest is more than 3.0 bar (in diesel engine 5.0 bar), this indicates a loose cylinder head gasket, faulty valves, worn piston rings and/or cylinder surfaces.
- When checking the compression, the engine oil temperature must be at least 30°C. The oil filter should be warm, warm up the engine if necessary.
- The battery must be fully charged.
Gas engine
- Switch off the ignition.
- Disconnect the electrical connectors from the ignition coils.
- Remove all spark plugs.
- Disconnect electrical connectors from all injectors.
6-cylinder petrol engine
- Disconnect the electrical connectors from the switches, which are located in the housing with the ignition coils.
Safety note
- Do not lean over the engine when checking compression. Escaping soot particles can cause injury.
- Turn the engine over with the starter so that soot particles are thrown out of the cylinders. Place the shift lever in neutral and apply the parking brake.
- Insert a compression pressure tester into the spark plug holes as directed in the owner's manual.
- The assistant should fully depress the accelerator pedal and hold it in this position until the entire check is completed.
- Rotate the engine crankshaft eight revolutions until the pressure rise as measured by the gauge stops.
- Check all cylinders one by one and compare the results with the given parameters.
- Connect the electrical connectors to the fuel injectors.
6-cylinder petrol engine
- Connect the electrical connectors to the switches.
- Screw in the spark plugs and tighten them to 30 Nm.
Attention. After disconnecting the electrical connectors, a fault message is stored in the memory of the engine control unit. It is recommended that this stored information be erased at an AUDI workshop as soon as possible.
Diesel engine
- Disconnect all electrical connectors from the fuel pump.
- Unscrew all glow plugs.
- Screw in a compression pressure tester with a flexible connecting hose instead of the glow plugs.
Attention. The compression pressure indicated in the table only applies when checking with the compression pressure tester VAG 1763 and adapter 1381/12 (engine 2.5-I: adapter 1763/5). When using other measuring instruments, it is only possible to check the compression deviation in one cylinder from another.
- Rotate the engine crankshaft eight revolutions until the pressure rise as measured by the instrumentation stops.
- Screw in the glow plugs and tighten them to 15 Nm. Connect wiring.
- Connect all electrical connectors to the fuel pump.
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