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Home >> GMC >> 1987 >> Forward Control 6.2 J, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Air Injection System - Vehicles Over 8500 GVW >> System Testing >> Air System
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Air System

  1. To determine if excessive noise is fault of Air Injection Reactor System, operate engine with air pump drive belt removed. If excessive noise does not exist with belt removed, inspect pump for damage.
  2. Inspect drive belt for wear, cracks or deterioration. Check for seized air pump. Check for improper pump mounting and bolt torque. Check for improper routing and connection of hoses. If none of these conditions exist and pump is still excessively noisy, replace air pump.
CAUTION: DO NOT  oil air pump. Pump will be damaged if any liquid is injected.
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