Air Injection Check Valve: Testing and Inspection

AIR INJECTION CHECK VALVE INSPECTION
1. A check valve should be inspected whenever the hose is disconnected from a check valve or whenever check valve failure is suspected. (An AIR pump that had become inoperative and had shown indications of having exhaust gases in the outlet port would indicate check valve failure.)

Caution: Before proceeding with the next check, make sure the check valve is cooled off. Also, tap on the check valve to remove any debris that may be inside the valve.

2. Blow through the check valve (toward the cylinder head) then attempt to draw suction back through the check valve. Flow should only be in one direction (toward the exhaust manifold). Replace valve which does not operate properly.