Visual Inspection

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Visual Inspection
WARNING: This page is about a different car, the 2004 GMC Sierra and 2004 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Normal operation-Brown to grayish tan with small amounts of white powdery deposits are normal combustion by-products from fuels with additives.
  2. Carbon fouled-Dry, fluffy black carbon, or soot caused by the following conditions:
    • Rich fuel mixtures
      • Leaking fuel injectors
      • Excessive fuel pressure
      • Restricted air filter element
      • Incorrect combustion
    • Reduced ignition system voltage output
      • Weak ignition coils
      • Worn ignition wires
      • Incorrect spark plug gap
    • Excessive idling or slow speeds under light loads can keep spark plug temperatures so low that normal combustion deposits may not burn off.
  3. Deposit fouling-Oil, coolant, or additives that include substances such as silicone, very white coating, reduces the spark intensity. Most powdery deposits will not affect spark intensity unless they form into a glazing over the electrode.
RENDER: 1.0x

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When to See a Mechanic

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

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