Crankcase Ventilation Systems: Maintenance

The positive crankcase ventilation system should be serviced every 12, 000 miles (25, 000 miles on 1977-79 models). Check hoses and hose connections for leaks. Disconnect all hoses and blow them out with compressed air. If any hose cannot be freed of obstructions, replace hose. Replace PCV valve (if equipped).

Fig 1: 1975-79 Datsun Crankcase Ventilation Systems

Courtesy of NISSAN NORTH AMERICA, INC.