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Mercedes Broken Catalytic Converter

The Importance of the Catalytic Converter in a Mercedes

by Mechanics Direct November 15, 2020

The catalytic converter is part of your Mercedes vehicle’s exhaust system. This also includes the engine and muffler. Malfunction of any one component of the exhaust system can lead to damage of another part or system.

Routine maintenance can prevent minor issues from escalating into very costly repairs. Let’s take a closer look at the catalytic converter and what to look for in situations that it might be damaged.

What is a catalytic converter?

The catalytic converter was invented in the 1950s to attempt to address harmful vehicle emissions that were plaguing cities with air pollution. This device was so successful in reducing harmful exhaust emissions that by the 1970s, catalytic converters were standard parts in practically all new vehicles being manufactured.

The exhaust system is responsible for dealing with the combustion products created when fuel is ignited to power the engine. After exiting the engine cylinders, harmful combustion gases run through the catalytic converter. The converter features a fine ceramic meshwork filter lined with such chemicals as platinum, palladium, and rhodium. These chemicals react with exhaust gases to convert them to less harmful gases. The reacted gases then pass through the muffler before safely leaving the vehicle by the exhaust valve to disperse into the air outside.

A vehicle may have a couple of catalytic converters, with one sitting right next to the engine and another farther away. The heat from the engine helps chemical reactions within the converter to run more efficiently. Multiple catalytic converters mean multiple parts containing the expensive elements mentioned before, like platinum. For this reason, catalytic converters have been known to be stolen. Manufacturers have since made efforts to place these components in harder to reach places to prevent theft.

How you notice a faulty catalytic converter

With a little knowledge about how catalytic converters work, you may be able to recognize any signs and symptoms of failure before it can cause an expensive problem. We have provided a list of signs of a faulty catalytic converter:


The catalytic converter is made to handle fuel exhaust fumes, not engine oil or coolant. Faulty cylinder head gaskets or breaks in the seals around the engine could cause other fluids to leak into the exhaust system. Oil or coolant can settle into and clog up the fine meshwork filter. Exhaust gases may not be able to move through and may not be able to be converted. You might notice dark exhaust fumes due to the unconverted gases. You could also smell sulfurous, “rotten egg” fumes, resulting from contaminants and raw exhaust.

Clogged catalytic converter

If exhaust fumes cannot flow through the meshwork of the catalytic converter, gases will back up toward the engine. Higher air pressures at the engine cylinders interfere with fuel combustion. This can cause decreased engine performance. You may find that your vehicle can’t go faster than a certain speed or has trouble accelerating.

Faulty spark plugs

Spark plugs ignite injected fuel to power the engine. If the injected fuel is not ignited in one cycle, a double volume of fuel may ignite in the next cycle. If this is happening, you will probably hear loud engine misfires. Such a large reaction will be very hot. High temperatures can melt components of the catalytic converter. You should be mindful of the engine temperature gauge.

Mechanics Direct will Fix a Faulty Catalytic Converter

If you suspect a problem with your catalytic converter, it is best to have your Mercedes seen by a professional who specializes in your brand and model. This part is purposefully difficult to reach due to its value, and a problem with one piece of the exhaust system can cause others to go bad as well. This means that a proper diagnosis is crucial to thoroughly resolve and repair these kinds of issues.

Mercedes Catalytic Converter Check

Mechanics Direct has years of experience and expertise working with Mercedes vehicles. We are the ideal professionals to return your vehicle to peak form. Our mechanics will communicate with you to develop a custom service plan for your Mercedes.

We are proud to be the Japanese and German vehicle experts for the North Chelmsford, Chelmsford, Dracut, Tyngsborough, and Westford areas. Call us today to speak to one of our technicians about how we can help.