Why does my catalytic converter overheat?


A combination of air and gasoline is forced into a combustion chamber where they’re burned and let out into the environment. Your vehicle’s exhaust emits toxic chemicals that pollute the atmosphere. This is where the catalytic converter comes in. The converter uses a catalyst that causes a chemical reaction. This reaction converts the harmful compounds into harmless compounds.

So, what causes your catalytic converter to overheat? There are a few factors that can be the underlying issue. Leaking fuel injectors can cause unburned fuel to burn inside of the converter instead. The extra fuel melts and overheats the substrate. When there is too much air in the combustion chamber a misfire can occur. This is called lean burn. Misfiring causes extra hydrocarbon buildup in the converter. This build-up will clog your converter and cause it to overheat!

A failing oxygen sensor is an oft-overlooked cause of overheating. Your converter links to oxygen sensors in your vehicle. These sensors are used to measure the mix of air and liquid fuel. If the mix is off and becomes too rich, your catalytic converter can overheat as a result. Catalytic converters usually run at 1200 to 1600 degrees Fahrenheit. An overheated converter turns bright red and becomes hotter than 2000 degrees Fahrenheit! This is dangerous for a number of reasons. If you have any concerns with your converter, bring it to an ASE-certified mechanic as soon as possible.