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Valve gear > < Removing and installing cylinder head

A4 Mk3

Checking compression
Checking compression
Special tools and workshop equipment required
   
t  Compression tester -V.A.G 1763- with adapter -V.A.G 1763/8-
  W00-0563
Procedure
l  Engine oil temperature approx. 80 °C.
l  Battery voltage at least 12.5 V.
–  Remove engine cover panel -arrows-.
  A10-11353
–  Unplug electrical connector -arrow- for fuel pressure regulating valve -N276- at fuel rail.
–  Briefly start engine to relieve fuel pressure in fuel rail.
–  Remove all glow plugs → Rep. gr.28.
  A23-10406
–  Screw in adapter -V.A.G 1763/8- in place of corresponding glow plug and connect compression tester -V.A.G 1763-.
  Note
Using the compression tester → Operating instructions.
–  Have a 2nd mechanic operate starter until tester shows no further pressure increase.
–  Repeat procedure on each cylinder.
  A15-11046
Compression pressurebar
When new25.0 … 31.0
Wear limit19.0
Maximum difference between cylinders5.0

Assembling
Installation is carried out in the reverse order; note the following:
–  Install glow plugs → Rep. gr.28.
–  Faults are stored in event memory of engine control unit because electrical connectors were unplugged and the engine was started: Interrogate event memory in Vehicle self-diagnosis → Vehicle diagnostic tester.
   

Valve gear > < Removing and installing cylinder head