1. Disconnect the crankcase ventilation hose from the valve and remove the crankcase ventilation valve.
2. Connect the valve to the crankcase ventilation hose.
3. Engine running (idling) put your finger on the open end of the valve and check for intake manifold vacuum.
4. Check the surface of the flexible hoses for thermal and/or mechanical damage. Signals of deterioration in their quality are the hardness and brittleness of the rubber, cracks, tears, cuts, abrasive damage and excessive swelling. Particular attention should be paid to those surfaces of flexible hoses that are close to strong heat sources such as the exhaust manifold.