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Home >> BMW >> 1979 >> 528i Automatic Trans >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Air Injection System >> Operation >> Check Valve
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Check Valve

This valve has a one-way diaphragm which prevents hot exhaust gases from backing up into the hoses and air pump. This protects the air injection system in case of pump belt failure, high exhaust system back-pressure, or air hose ruptures.