The exhaust manifold acts as a funnel, collecting the exhaust gases from all cylinders of the engine then releasing them through a single opening, often referred to as the front pipe. Catalytic Converters (CAT’s) are an integral part of a car’s engine management system, not simply a part of the exhaust system.
The CAT Can Fail because of Carbon pollution where un-burnt fuel, oil or antifreeze enters the exhaust system, leading to a partial or complete blockage. This could hamper your cars performance and make the exhaust system noisy.