Compression check (Audi A6 C4)

If the engine runs poorly or intermittently, perform a compression test. Regularly performing this test will allow you to prevent malfunctions in advance.

To perform the test, you will need a tester designed for diesel engines. Connect the tester to the adapter and screw the adapter into the glow plug hole or into the injector hole.

The engine must be warmed up, the battery charged, the spark plugs and injectors unscrewed, the wires of the shut-off valve and fuel block disconnected.

The pressure in all cylinders should be the same. A difference of more than 0.5 bar between any two cylinders indicates a malfunction. In a healthy engine, the pressure should build up quickly. Low first-stroke pressure that gradually builds up with subsequent strokes indicates worn piston rings. Low first-stroke pressure that does not build up with subsequent strokes indicates a valve leak or a blown head gasket. Deposits on the bottom of the valves can also cause low compression. Low pressure in two adjacent cylinders almost always means a blown head gasket between them.

If you have any difficulties during the inspection, please contact the specialists.