Q: How Can I Check and Replace a Malfunctioning Catalytic Converter?
A: A catalytic converter (or catalyst) is an emission control device that reduces certain pollutants in the exhaust gas stream, with two types available: an oxidation catalyst reducing hydrocarbons (HC) and carbon monoxide (CO), and a reduction catalyst reducing oxides of nitrogen (NOx). To check a malfunctioning converter, expensive test equipment is needed, so it's best to consult a dealer or authorized emission inspection facility for diagnosis and repair. During underbody servicing, inspect the converter for leaks, corrosion, dents, and other damage, and replace it if necessary. To check for a restricted converter, use a vacuum gauge to diagnose the effect of a blocked exhaust on intake vacuum. If the exhaust system is restricted, it might indicate a plugged catalytic converter or a restricted exhaust pipe or muffler. For replacement, spray penetrant on exhaust pipe-to-exhaust manifold bolts and clamp bolts to loosen them up. Disconnect and remove Oxygen Sensors. Unscrew upper exhaust pipe-to-exhaust manifold flange bolts and loosen the clamp securing the slip joint between the two sides of the crossover pipe. If replacing the right catalytic converter, also loosen the clamp securing the slip joint between the right exhaust pipe and the premuffler. Remove the catalytic converter assembly, discard the old flange gasket, and install a new one during reinstallation using new bolts and clamps as recommended by Dodge. Coat threads with anti-seize compound for ease of future removal and tighten all fasteners securely.