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Home >> GMC >> 1972 >> G25/G2500 Van Base >> Repair and Diagnosis (Single Page) >> Engine Mechanical >> Mechanical >> Crankcase Ventilation Systems >> System Checking >> Testing PCV Valve
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Testing PCV Valve

  1. Connect tachometer and vacuum gauge to engine, set parking brake, start engine and adjust idle speed and mixture.
  2. Disconnect ventilation hose at PCV valve, block opening of valve and read engine RPM change.
  3. A change of less than 50 RPM indicates a plugged PCV valve.
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