PCV Valve
Replace valve every 12 months or 12, 000 miles (1966-71) or every 24 months or 24, 000 miles (1972 and later). On 1972 and later models, if vehicle is operated under severe conditions (extreme dust, prolonged idling, trailer towing or short trips in cold weather) replace valve every 12 months or 12, 000 miles. When replacing PCV valve, rest of system should be serviced by washing parts in solvent and blowing out hoses with compressed air.