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Catalytic Converter GMC Vandura I

Testing & Diagnostics 2 illustrations ~308 words

DESCRIPTION & OPERATION

Note. Light Duty Emission vehicles are those vehicles whose Gross Vehicle Weight (GVW) does not exceed 8500 lbs.

The catalytic converter(s) is installed in the exhaust system in front of the muffler, so that all exhaust gas must pass through the converter(s). The converter is a stainless steel muffler-shaped device that reduces exhaust emissions.

The catalyst reduces hydrocarbons (HC) and carbon monoxide (CO) emissions. The material inside the converter is 1 of 2 types: a coated 1-piece honeycombed block (monolithic type), or small beads of catalyst-coated material.

Note. Use ONLY unleaded fuel in vehicles using catalytic converters. If leaded fuel is used, the Tetra Ethel Lead will coat the palladium, platinum and rhodium, rendering these catalysts inoperative. If this happens, the converter must be replaced.

HEAT SHIELDS

The combustion reaction, which is furthered by the converter, releases additional heat. Temperature in the catalytic converter can reach 1600°F (871°C) under normal conditions. Special heat shields are used to protect underbody and components from this extreme heat.

Fig. 1: Cutaway View of Bead-Type Catalytic Converter Beads may be replaced.
Scheme 1: Cutaway View of Bead-Type Catalytic Converter Beads may be replaced.

MAINTENANCE

There is no scheduled maintenance required for catalytic converters. However, on vehicles with bead-type converters, bead removal and replacement is possible.

Scheme 75

Scheme 75: BOTTOM COVER REPLACEMENT
Scheme 75: BOTTOM COVER REPLACEMENT
  1. Using a hand or power tool, remove bottom cover by making a shallow, close cut to bottom outside edge. (Scheme 75): Removal of Converter Bottom Cover Make a shallow cut; avoid damage to inner shell.
  2. Remove insulation and check inner shell for damage. If damage is found, entire converter must be replaced.
  3. If no damage is found, position new insulation into replacement cover. Apply sealer (8998245 or equivalent) around edge of cover, using extra sealer at front and rear pipe openings.
  4. Install replacement cover on converter, and position retaining channel along edges. Complete the installation by attaching clamps (provided with replacement cover) to both ends of converter.

COMPONENT TESTING

Note. Testing information not available.

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