Overheating catalytic converters are a fire risk that's often overlooked, but think about it: One of the consistently hottest parts of your car runs the entire length of the vehicle -- the exhaust system. Catalytic converters usually overheat because they are working too hard to burn off more exhaust pollutants than they're designed to process. In other words, if the car's engine isn't operating efficiently (due to worn spark plugs or any number of other adverse conditions), it doesn't burn the fuel properly, and a lot of extra stuff ends up in the exhaust system. The cat then has to work extra hard to do its job, which makes it even hotter than usual. An overworked (or clogged) catalytic converter can easily go from its normal operating temperature range of about 1,200 to 1,600 degrees Fahrenheit (648.9 to 871.1 degrees Celsius) to up over 2,000 degrees Fahrenheit (1,093.3 degrees Celsius). This causes long-term damage not only to the cat itself, but to the car's surrounding parts. The car's designed to withstand the cat's normal temps, but it can't consistently cope with temperatures several hundred degrees higher. If the catalytic converter gets hot enough, it could ignite the cabin insulation and carpeting right through the heat shields and metal floor pan.