Vauxhall Workshop Service and Repair Manuals

Engine Pressure Loss, Check

Unscrew all spark plugs with engine at operating temperature.

Hold throttle valve fully open. In order to listen to intake manifold and crankcase to determine if bubble formation is present, remove air cleaner, oil filler cap and expansion tank cap.

Connect pressure loss tester to compressed air system and calibrate.

Position piston of Cylinder 1 at "TDC".

In this position, valves of Cylinder 1 are closed and valves of Cylinder 4 are crossing. Distributor rotor aligns with mark on distributor housing.

Screw connecting hose into spark plug bore of Cylinder 1 and attach to connecting hose.

Crankshaft must not turn during this operation.

Attention: If crankshaft has turned, detach connecting hose, correct crankshaft position and re-attach hose.

Read off pressure loss in percent from gauge. Simultaneously listen for compressed air escaping from intake manifold, exhaust system or crankcase. Check for bubble formation in coolant expansion tank.

Total pressure loss per cylinder should not exceed 25% (at piston approx. 5%, at valves approx. 20%). Approximate individual values can only be estimated by ear.

Difference between individual cylinders must not exceed 10%.

Remove connecting hose from cylinder 1 and connect to cylinder 3.

Turn crankshaft until next piston is at "TDC".

Ignition sequence: 1-3-4-2

Make marks to aid in determining "TDC" position on distributor.

Use dwell angle tester or test lamp as aid if necessary. On DOHC engine take off rotor and remove inner seal. Replace rotor and make marks.

Note:

If compressed air can be heard blowing from cylinder under pressure into adjacent cylinder (can be heard at open spark plug bore), cylinder head gasket is leaking.

Test cylinders 4 and 2 in the same way.