The main function of your catalytic converter is to convert harmful gasses in your exhaust into safer elements before they are emitted by your vehicle. Most converters are made from thin and fragile ceramic, and their operation is delicate and relies on the proper functioning of many other engine and exhaust components. This means that issues with your converter will usually indicate further damage to your exhaust system or engine, which is actually a good thing for your vehicle’s health – since catalytic issues are very easy to spot in their early stages (relative to most engine and exhaust damage), it will allow you to get the rest of your engine fixed before the damage gets too serious.
Unburned fuel leeching into the exhaust system –
Your vehicle’s fuel needs to be fully burned in the combustion chamber before entering the exhaust system; otherwise the fuel can ignite when it reaches the converter and cause overheating and eventual melting. Leaking fuel into your exhaust can be caused by a number of engine issues, but most commonly you will be having problems with the fuel injector or check valve.
Malfunctioning oxygen sensor –
If your vehicle’s oxygen sensor isn’t functioning properly, it can lead to the exhaust gas being too thin or too thick. If it is too thin your catalytic converter won’t be able to convert the harmful gases to safer elements, leading to your vehicle failing an emissions inspection. If the exhaust gas is too rich it will cause the converter to overheat and melt.
Leaking oil or anti-freeze –
If any of your engine’s oil or anti-freeze enter the exhaust, it can block the air pathway by coating a thick layer of soot over the ceramic exterior of the catalytic converter. At first this will reduce the converter’s performance, but eventually the carbon soot will block the pores of the ceramic and block the release of exhaust. This causes heat to build up in your exhaust system, leading to extensive damage.
Damage from road debris –
Because your vehicle’s catalytic converter is relatively fragile, pebbles and other pieces of degree can strike the exterior and lead to fracturing. This is when you start to hear a rattling sound coming from your exhaust system (due to pieces of the converter’s casing breaking off inside the exhaust. Again, this will block the flow of the exhaust gasses and cause heat build-up in your engine, eventually causing a meltdown.
Remember that damage to the catalytic converter is usually tied into damage to other engine and exhaust components – it is highly recommended you take your car into a mechanic for a full inspection if you’re having any problems with exhaust heat or emission.