GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2004 🢒 TrailBlazer - 2WD 🢒 Engine 🢒 Engine Mechanical - 4.8L, 5.3L, and 6.0L 🢒 Oil Pan Cleaning and Inspection

    Object Number: 1215984 Size: SH

    Important: When installing a NEW oil pan gasket, it is not necessary to install the rivets that retain the NEW gasket to the pan.

  1. Remove the oil transfer tube bolts (435, 446) and gaskets (445, 448).
  2. Remove the oil transfer tube (447).
  3. Inspect the tube for damage or restrictions.

    4. Object Number: 1215985 Size: SH
  4. Remove the plugs from the oil galleries.

    5. Object Number: 825846 Size: SH
  5. Remove the oil pan baffle and bolts.

    6. Object Number: 825832 Size: SH
  6. Remove the oil pan drain plug and O-ring seal.
  7. Clean the oil pan in solvent. Be sure to thoroughly clean all of the oil passages and recesses of the pan.
  8. Clean the oil pan gasket surfaces. Refer to Replacing Engine Gaskets .

    9. Caution: Refer to Safety Glasses Caution in the Preface section.

  9. Dry the oil pan with compressed air.
  10. Inspect the gasket sealing surfaces for excessive scratches or gouging. Refer to Replacing Engine Gaskets .
  11. Inspect the oil pan drain plug and threaded drain hole for damaged threads.

    12. The drain plug O-ring seal may be used again, if not cut or damaged.


    Object Number: 1272831 Size: SH
  12. Inspect the oil filter sealing surface for scratches or gouging.
  13. Inspect the oil filter fitting (438) for a loose fit or damaged threads.
  14. Inspect the oil passages for restrictions.
  15. Inspect the oil filter bypass valve (436) for proper operation.

    16. Lightly depress the bypass valve. The valve spring should seat the valve to the proper position.