Mazda CX-5 Service & Repair Manual: Positive Crankcase Ventilation (PCV) Valve Inspection

Airflow Inspection

1. Disconnect the section (A) of ventilation hose shown in the figure.

2. Start the engine and verify that vacuum is applied to the end of the disconnected ventilation hose while the engine is idling.

• If vacuum is not applied to the ventilation hose, perform the procedure from Step 3.

NOTE:

• If the PCV valve is operating normally, vacuum occurs in the ventilation hose, however, if the PCV valve is not operating normally, vacuum does not occur in the ventilation hose because the blow-by gas is circulated to the air hose from the ventilation hose.

• Verify the ventilation hose vacuum as follows:

• When the tip of your figure is touching the end of the ventilation hose, the tip of your figure is suctioned by the hose.

• When a thin scrap of paper is contacting the end of the ventilation hose. the paper is suctioned by the hose.

3. Disconnect the negative battery cable..

4. Remove the intake manifold..

5. Remove the PCV valve and the oil separator as a single unit..

6. Verify that there is no airflow when pressure is applied to port B.

• If there is airflow, replace the PCV valve and the oil separator as a single unit..

7. Verify that there is airflow when vacuum is applied to port B.

• If there is no airflow, replace the PCV valve and the oil separator as a single unit..