Audi Workshop Service and Repair Manuals

Checking compression

Special tools and workshop equipment required

t	Spark plug socket and extension -3122 B-

t	Compression tester -V.A.G 1763-

t	Puller -T40039-

Procedure l  Engine oil temperature at least 30 °C. l  Battery voltage at least 12.5 V. –  Switch off ignition. –  Pull off engine cover panel (rear) -arrows-.

–  Remove cover -1- on left side of engine compartment.

–  Unbolt coolant expansion tank -arrow-. –  Unplug electrical connector for coolant shortage indicator switch -F66- at expansion tank (bottom) and move expansion tank to one side (coolant hoses -1 ... 3- remain attached).

–  Remove cover -1- at right of engine compartment.

–  Remove bolts -arrows-. –  Disengage activated charcoal filter solenoid valve 1 -N80--item 1- at air duct. –  Remove air duct -2-.

–  Remove air cleaner housing -arrows-. –  Unplug electrical connector -1- at air mass meter -G70-. –  Remove air intake hose -2- with air mass meter -G70-.

–  Unscrew bolts -4- and -5- on cylinder head cover (left-side). –  Unplug electrical connectors -1 ... 3- and -6-. –  Pull out ignition coils -arrows- using puller -T40039-.

–  Unscrew bolts -5- and -6- on cylinder head cover (right-side). –  Unplug electrical connectors -1 ... 4-. –  Pull out ignition coils -arrows- using puller -T40039-. –  Remove spark plugs with spark plug socket -3122 B-.

–  Unplug all electrical connectors at all injectors; to do so, release connectors on underside -arrow-. –  Test the compression pressure with the compression tester -V.A.G 1763-.   Note Using the compression tester → Operating instructions. –  Have a 2nd mechanic press down the accelerator pedal completely and simultaneously operate the starter until the pressure no longer increases on the tester display.

Compression pressure	bar
When new	10.0 … 14.0
Wear limit	9.0
Difference between cylinders	3.0 (maximum)

Installation is carried out in the reverse order; note the following: –  Install spark plugs → Rep. Gr.28. –  After checking compression pressure, interrogate fault memory of engine control unit and erase it as necessary → Vehicle diagnosis, testing and information system VAS 5051.