GM 8999979 Catalytic Convertor

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Situated below the vehicle in the exhaust system, a catalytic converter is a muffler-like unit. It aims to minimize the release of hydrocarbon (HC) and carbon monoxide (CO) pollutants into the atmosphere. A 49 States and High Altitude model X-Bodies utilize this kind of converter which has small beads that are coated with platinum and palladium. These beads facilitate chemical reactions that convert CO to CO2 and HC to CO2 and H20. The Phase II Monolith converter is used in California version X-Bodies, which have an internal design like honeycomb coated with platinum as well as rhodium in addition to platinum. This catalyst also helps reduce oxides of nitrogen in addition to HC and CO. Keeping it working effectively requires using only unleaded fuel. Periodic maintenance isn't necessary but the life span of this converter is limited hence must be replaced after every 30,000 miles approximately. When the useful life of the catalyst has been depleted, a 'catalyst' reminder light appears on the speedometer. If for any reason a bead-type converter becomes useless, replace it with a new one or drain off and replace beads inside it. The Monolith converter cannot have its catalyst replaced separately. If a bead-type converter's bottom gets damaged, it can be replaced without removing the entire thing. Note that the converter operates at very high temperatures so care must be taken when working near or on it so as not to get burnt.

Remove bolts at the flange at the rear end, loosen nuts, remove U-clamp, and slide the catalyst out of the outlet pipe.

No, periodic maintenance is not required for the catalytic converter.

The catalytic converter needs to be renewed after approximately 30,000 miles.