Ventilation & Check Valve
- Disconnect hoses "A" and "B" from valve. Start engine and allow it to idle. Check vacuum at port "A". See Figure.
- If vacuum is present, place finger over port "A" and check vacuum at port "B". If vacuum is present, continue holding finger over port "A" and disconnect port "C", making sure there is no vacuum at port "B".
Courtesy of MAZDA MOTORS CORP.
- Stop engine. Disconnect hose "D" and attach suitable length of hose. Blow through valve and make sure air does not pass through. If valve fails any test, it must be replaced.