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Home >> BMW >> 1978 >> 633CSi Standard Trans >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Air Injection Systems >> Check Valve & Relief Valve
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Check Valve & Relief Valve

The relief valve vents excessive pressure which may build up in air injection system. The check valve has a one-way diaphragm which prevents hot exhaust gases from backing up into hose and pump. Valve protects system in case of pump belt failure, high exhaust system pressure, or air hose ruptures.