GM 25057843 Catalytic Converter Assembly

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The catalytic converter is an emission control device that reduces hydrocarbon and carbon monoxide pollutants in the exhaust system. It contains beads coated with platinum and palladium, and it is important to use only unleaded gasoline to prevent lead contamination and reduce combustion chamber deposits and corrosion. While periodic maintenance is not required, it is advisable to inspect the converter and related exhaust components during other service. If the converter is ineffective, it can be replaced or the coated beads can be drained and replaced. Caution should be exercised when working near the converter due to its high temperatures, and proper lifting pads should be used to avoid damage. There are no functional tests for the home mechanic to determine if the converter is working properly. In the rare event that the converter needs to be replaced, the car should be raised and supported securely, and the converter should be disconnected at the front and rear using penetrating oil if necessary. The inlet and outlet converter flanges can then be separated from the exhaust pipes, and the converter can be removed from under the vehicle. Installation is the reverse of the removal process, using new nuts and bolts. There are two types of catalytic converters, and if the monolith converter fails, it must be replaced entirely. The catalyst in bead type converters can be changed by draining and filling the beads through a plug at the bottom of the converter. This process is best done by a dealer with specialized equipment, but it can also be done with the converter removed from the car. To fill the converter with new beads, it should be raised at a 45-degree angle and the beads should be poured in while tapping lightly on the converter belt. A special service fill plug is required to replace the stock one, and it should be installed according to the provided instructions. Finally, the converter should be installed, the engine started, and checked for leaks.

If the converter is ineffective, it can be replaced, or the coated beads can be drained and replaced.