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Air Check Valve

  1. Visually inspect thermactor hoses, tubes, control valve(s) and check valve(s) for leaks from exhaust gas backflow. If holes are found and/or traces of exhaust gas products are evident, check valve may be suspect.
  2. Valve should allow free flow of air in direction of arrow only. See Fig 1 . The valve(s) should check (or block) free flow of exhaust gas air in opposite direction.
  3. If air does not flow as indicated or if exhaust gas backflows opposite of direction of arrow in illustration, replace check valve.
Fig 1: Testing Air Check Valve
G90E14328Courtesy of FORD MOTOR CO.