Nissan 240SX/Altima 1993-1998 Repair Guide

PCV Valve


Proper operation of the crankcase ventilation system is important to maintaining low emissions levels and long engine life. A malfunctioning PCV system will (1) allow blow-by gases to escape into the atmosphere, polluting the air or (2) allow blow-by gases to remain in the crankcase, contaminating the engine oil and causing the formation of sludge.

For more information on the Positive Crankcase Ventilation (PCV) system, please refer to Driveability & Emissions Controls of this guide.

Although the manufacturer does not give a specific inspection or replacement schedule,it is a good idea to inspect/replace the PCV valve at 30,000 mile (48,300 km) intervals.


Refer to the Crankcase Ventilation System coverage in Driveability & Emissions Controls for PCV valve removal and installation.