Used Check Valve (Smog) 1990–2019

A stuck-open smog check valve lets hot exhaust gases flow back into the air pump and hoses, melting the hoses and destroying the pump over time. By the time you smell something burnt from the engine bay and see a deformed air injection hose, the pump is usually not far behind. The smog check valve is a one-way valve in the air injection system that prevents exhaust gases from flowing back into the air pump. It sits between the air pump outlet and the exhaust system. Redline stocks used smog check valves from emissions systems on cars and trucks across the country. With 15 listings from 6 sellers covering 9 makes -- including common emissions applications from Chevrolet, Mercedes Benz, Honda, Infiniti, Ford -- you can replace a failed valve without paying dealership prices. Filter by year, make, and model to find a compatible valve. These are small and inexpensive used, making them an affordable fix before replacing the entire air injection system.