Crankcase ventilation system check (Every 12 000 miles (20 000 km) or 12 months)

1 Inspect the crankcase ventilation system for blockage or damage. A blocked hose can cause a build-up of crankcase pressure, which in turn can cause oil leaks (see illustration).

35.1 Loosening the crankcase ventilation hose clip - CVH models
35.1 Loosening the crankcase ventilation hose clip - CVH models

2 On carburettor model SOHC engines, clean the oil filler cap with paraffin and check that the vent valve is not blocked by pulling it from the oil separator and loosening the hose clip (Section 42).

3 On CVH engines, check that the oil separator and mushroom valve are not blocked, and clean if necessary (see illustration).

35.3 Oil separator (1) and mushroom valve (2) locations in air cleaner - CVH
35.3 Oil separator (1) and mushroom valve (2) locations in air cleaner - CVH models

    See also:

    Brake hydraulic system (conventional braking system) - bleeding
    Caution: Refer to the precautions in Section 1. General 1 If any of the hydraulic components in the braking system have been removed or disconnected, or if the fluid level in the reservoir has b ...

    Fluid reservoir (ABS) - removal and refitting
    Note: New seals must be used between the reservoir and the hydraulic unit on reassembly. Caution: Refer to the precautions in Section 1. Removal 1 Disconnect the battery negative lead. 2 Depress ...

    Cylinder head - removal and refitting (engine removed)
    Note: The cylinder head bolts must always be renewed after slackening, and a new cylinder head gasket and camshaft cover gasket must be used on refitting. If the engine has recently run, the cylin ...