Bimetallic Vacuum Switching Valve

Disconnect both vacuum hoses from valve, located under intake manifold. Connect a hose to either port on valve. Blow through hose. With engine coolant temperature less than 131°F (55°C), air should not pass through valve. With engine coolant temperature greater than 149°F (65°C), air should flow through valve. If valve does not operate as described, replace valve.