1983 GMC Forward Control 5.7 M, StandardFACTORY OEM SERVICE PROCEDURE

Description & Operation: Notes

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.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.