Failures - Carbon Deposits:
This increases back pressure and causes the entire exhaust system to heat up. The heat backs up into the engine compartment and may result in a number of heat-related engine problems. Mild carbon scoring may do less damage to engine components but it may seriously affect the converter’s ability to reduce harmful emissions. It could easily cause a vehicle to fail an emission test. Carbon deposits may be the result of faulty valves, worn piston rings, worn or leaking gaskets or lead in the fuel.