Tools Required

J 39946  Crankshaft Socket - 4.0 L and 4.6 L

1. Ensure the crankshaft is in the TDC position for the number one cylinder using the J 39946. 
   CAUTION: Ensure each valve lifter is filled with clean engine oil and the valve lifter does not tip over (plunger down) before the installation of the valve lifters. The loss of oil in the valve lifter lower pressure chamber or the dry stroking/cycling of the valve lifter plunger will allow air to travel into the high pressure chamber of the valve lifter. Air in the high pressure chamber of the valve lifter may not be purged causing extensive engine component damage.
2. Fill the stationary hydraulic lash adjuster (SHLA) with clean engine oil GM P/N 12378006 or equivalent. Take precautions to prevent scratching the pivot sphere area (1) of the SHLA.
3. Lubricate the SHLA bores of the cylinder head with clean engine oil GM P/N 12378006 or equivalent.
   Fig 1: Locating Stationary Hydraulic Lash Adjuster

   Courtesy of GENERAL MOTORS CORP.
4. Install the SHLAs.
5. Apply a liberal amount of lubricant GM P/N 12345001 or equivalent to the SHLA sphere.
   Fig 2: Installing Stationary Hydraulic Lash Adjusters

   Courtesy of GENERAL MOTORS CORP.