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PCV System Test Procedure

  1. Disconnect PCV hose.
  2. Start engine.
  3. Check for vacuum at hose. If there is no vacuum, check for a plugged hose or manifold port. Check for a hose that collapses when blocked (vacuum applied). Replace plugged or deteriorated hoses.
  4. Allow engine to idle at normal operating temperature.
  5. Remove engine oil dipstick and install a vacuum gauge on dipstick tube.
  6. Block off PCV system fresh air intake passage.
  7. Run engine at 1500 RPM for 30 seconds, then read vacuum gauge while engine is running at 1500 RPM.
    • If vacuum is present, this indicates that the crankcase ventilation system is functioning properly.
    • If no vacuum is indicated, the engine may not be sealed and is drawing in outside air. Check valve covers, oil pan gasket, or other sealing areas for leaks.
    • If vacuum gauge registers a pressure or if vacuum gauge is pushed out of dipstick tube, check for a plugged PCV port, a plugged hose or excessive engine blow-by.
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