Audi Workshop Service and Repair Manuals

Checking compression

Special tools and workshop equipment required

t	Hose clamps for hoses up to 25 mm -3094-

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.

–  Unplug electrical connector at engine speed sender -G28--arrow- on left side of gearbox (carefully bend heat shield to one side).

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

–  Clamp off coolant hose -2- using hose clamp -3094- and detach from coolant expansion tank. –  Seal off connection with a suitable plug. –  Unbolt coolant expansion tank -arrow-. –  Unplug electrical wire for coolant shortage indicator switch -F66- at expansion tank (bottom) and move expansion tank to one side (coolant hose -1- remains attached).

–  Pull dipstick -1- out of guide tube. –  Remove bolts -2- and -3-. –  Unplug electrical connectors at ignition coils. –  Push wiring harness to one side.

–  Remove bolts -arrows-. –  Remove air ducts -1- and -2-.

–  Remove bolts -1- and -2-. –  Unplug electrical connectors at ignition coils. –  Push wiring harness to one side.

–  Pull all ignition coils out with puller -T40039-. –  Remove spark plugs with spark plug socket -3122 B-. –  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. –  Repeat procedure on each cylinder.

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

Assembling Installation is carried out in the reverse order; note the following: –  Install spark plugs → Booklet803 or → Booklet805. –  Faults are stored in engine control units because connectors were unplugged: “Generate readiness code” in “Guided Functions” → Vehicle diagnosis, testing and information system VAS 5051. Tightening torque

Component	Nm
Wiring guide for ignition coils to cylinder head cover	5