2. Disconnect the hose, unscrew the PCV valve from the cap, then connect the hose.
38.2a. Disconnect the hose from the PCV valve...
3. With the engine idling at normal operating temperature, place your finger on the valve opening. If there is no vacuum at the valve, the valve or hose is clogged. Replace old or clogged hoses.
(The article is reprinted from a web resource: www.MitsubishiMan.ru)
4. Turn off the engine. Disconnect the PCV valve from the hose. Apply compressed air to the valve from the threaded end. If air does not pass through the valve in this direction, replace the valve.
5. When purchasing a new PCV valve, make sure the valve is compatible with your vehicle and engine. Compare the old valve with the new one.