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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1819 (Engine Mechanical - 3.5L (L66)) >> Repair Instructions >> Off Vehicle Repair Instructions >> Valve Guide Reaming/Valve and Seat Grinding >> Valve Guide Replacement

Valve Guide Replacement

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
    Fig 1: Heating Cylinder Head
    GM897382Courtesy of GENERAL MOTORS CORP.
    IMPORTANT: Do not heat the cylinder head in excess of 150°C (300°F). Excessive heating of the cylinder head may loosen the valve seats.
  1. Select the proper replacement guides and chill them in a freezer for approximately 1 hour.
  2. Use a hot plate or an oven to evenly heat the cylinder head to 150°C (300°F). Monitor the temperature with a thermometer.
  3. Fig 2: Driving Guide Out Of Cylinder Head
    GM897384Courtesy of GENERAL MOTORS CORP.
  4. Working from the camshaft, or top, side, use the EN 46341  and an air hammer in order to drive the guide approximately 2 mm (0. See Special Tools .1 in) towards the combustion chamber. This action will remove some of the carbon from the guide and ease in guide removal.
  5. IMPORTANT: Drill the guides only in extreme cases. Use extreme care not to break the guide and damage the cylinder head.
  6. Turn the head over and use the EN 46341  and an air hammer to drive the guide out of the cylinder head. See Special Tools . If the valve guide will not move, enlarge the guide bore with an 8 mm (5/16 in) drill bit.
  7. Fig 3: Measuring The Guide For The Properly Installed Height
    GM897385Courtesy of GENERAL MOTORS CORP.
  8. Use the EN 46341  in order to install the NEW guides into the cylinder head. See Special Tools . Remove the valve guides, 1 at a time from the freezer, just prior to installation.
  9. Measure the guide (264) for the properly installed height (a).

    Specification: 

    • Intake valve guide installed height: 21.20-22.2 mm (0.835-0.874 in)
    • Exhaust valve guide installed height: 20.63-21.63 mm (0.812-0.852 in)

  10. Fig 4: Reaming Guide Bore
    GM897386Courtesy of GENERAL MOTORS CORP.
  11. Coat the EN 46345  and the valve guide with cutting oil. See Special Tools .
  12. Use the EN 46345  to ream the guide to the proper size. See Special Tools . Rotate the reamer clockwise the full length of the guide bore. Continue to rotate the reamer clockwise while removing from the guide bore.
  13. Clean the guide in detergent and water to remove cutting residue.
  14. Measure the valve stem-to-guide clearance. The valve should slide freely in the guide without exerting pressure.