GM Service Manual Online
For 1990-2009 cars only

    Important: 

       • DO NOT allow dirt or debris to enter the oil passages of the Valve Lifter Oil Manifold (VLOM). Plug, as required.
       • DO NOT disassemble the electrical components from the VLOM.
       • DO NOT submerge the electrical components in cleaning solvent.
       • DO NOT use the VLOM outer gasket again. Remove the VLOM outer gasket and install a NEW VLOM outer gasket during assembly.


    Object Number: 2044001  Size: SH
  1. DO NOT lift the VLOM (2) by the electrical lead frame (1).

  2. Object Number: 2044519  Size: SH
  3. Remove the oil pressure sensor (1) and washer (2) from the VLOM (5).
  4. Important: The valve lifter oil filter (3) should be replaced whenever the oil pressure sensor (1) is removed.

  5. Remove the valve lifter oil filter (3).
  6. Discard the filter

    Important: The valve lifter oil filter O-ring seal (4) is a single use only part and must be replaced whenever the valve lifter oil filter (3) is removed.

  7. Remove and discard the valve lifter oil filter O-ring seal (4).
  8. Discard the O-ring seal

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

  9. Clean the VLOM (5) with compressed air.

  10. Object Number: 2044520  Size: SH
  11. Inspect for loose electrical solenoids (1-4) for loose or missing bolts.
  12. Inspect for damage to the electrical lead frame (5).
  13. Inspect for a damaged electrical connector, for bent or corroded pins.

  14. Object Number: 2044521  Size: SH
  15. Inspect for damaged VLOM inner gaskets (1-8). If the VLOM inner gaskets are damaged, the VLOM must be replaced as an assembly.
  16. Inspect for a damaged VLOM outer gasket (9) or scored gasket surfaces.
  17. Inspect for debris or restrictions within the oil passages of the VLOM. Refer to Cylinder Deactivation (Active Fuel Management) Valve Lifter Oil Manifold Diagnosis and Testing.