Common Catalytic Converter Problems

Catalytic converter problems should be diagnosed and repaired as quickly as possible to reduce harmful emissions and to improve the efficiency of your vehicle.

The Causes Of Common Catalytic Converter Problems

Since catalytic converters are passive, they don't wear out in the typical sense. A problem with your catalytic converter is always caused by a problem with another part of your vehicle. Here are some of the most common problems:

• Catalytic congestion. Your catalytic converter may become "plugged" by deposits created by burned oil, a too-rich fuel mixture or frequent short trips that don't allow the converter to reach the proper operating temperature. Loose sparkplug wires or fouled plugs can lead to this problem, as can problems with exhaust valves.
• Surface contamination. Contaminants in the exhaust gases can coat the surfaces of the inside of the catalytic converter, leading to reduced efficiency. Oil leaks can leave phosphorus deposits and create blue exhaust smoke. Engine coolant leaks can leave silicon deposits and produce white exhaust smoke. A drop in catalytic converter efficiency is usually revealed via an emissions test.
• Bad information. The modern catalytic converters rely on a proper air/fuel mixture to achieve maximum efficiency. A closed loop system uses oxygen sensors to monitor and change the mixture. Fouling or damage to the oxygen sensors will cause problems with the operation and efficiency of the catalytic converter. On modern vehicles, engine scan codes can reveal oxygen sensor issues.
• Physical damage. Since the catalytic converter is installed underneath the car, it is subject to damage from obstructions or debris. A hot catalytic converter my also crack if it is exposed to snow or ice. These issues can be avoided with careful driving habits.