Heat Shield: Description and Operation

CAUTION:
- Avoid application of rust prevention compounds or undercoating materials to exhaust system heat shields on cars if equipped. Light over spray near the edges is permitted. Application of coating will greatly reduce the efficiency of the heat shields resulting in excessive floor pan temperatures and objectionable fumes.

- Do not remove spark plug wires from plugs or by any other means short out cylinders if exhaust system is equipped with catalytic converter. Failure of the catalytic converter can occur due to temperature increases caused by unburned fuel passing through the converter.

PURPOSE
Heat shields are needed to protect both the car and the environment from the high temperatures developed in the vicinity of the catalytic converters and muffler. Each catalytic converter has a integral heat shield attached to it and are not to be removed.

REACTION
The combustion reaction caused by the catalyst releases additional heat in the exhaust system. Causing the temperature to increase in the area of the reactor under severe operating conditions. Such conditions can exist when the engine misfires or otherwise does not operate at peak efficiency. The use of the catalysts also involves some non-automotive problems. Unleaded gasoline must be used to avoid poisoning the catalyst core. Do not allow engine to operate above 1200 RPM in neutral for extended periods over 5 minutes. This condition may result in excessive exhaust system/floor pan temperatures because of no air movement under the vehicle.