Tools Required

Important: 

•	Any time the camshaft housing to the cylinder head bolts are loosened or removed, the camshaft housing to the cylinder head gasket must be replaced.

•	During disassembly, ensure that the valve lifters are kept together and identified so that they can be reinstalled in the original locations.

•	Before disassembling the valve mechanism, make a compression test and note the results. Refer to Engine Compression Test .

1. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical .



2. Remove the ignition coil and the module assembly. Refer to Ignition Control Module Replacement in Engine Controls.
3. Remove the camshaft position sensor connector.



4. Remove the power steering pump and position aside.

Do not disconnect the power steering lines.

5. Disconnect electrical from oil pressure sensor.
6. Remove the vacuum line from the fuel pressure regulator.



7. Remove the fuel rail. Refer to Fuel Injection Fuel Rail Assembly Replacement in Engine Controls.
8. Disconnect, but do not remove from the vehicle, the timing chain housing at the intake camshaft housing. Refer to Timing Chain Housing Replacement .



9. Remove the camshaft housing cover to the camshaft housing retaining bolts.




Important: 

•	Use the reverse of the tightening procedure when loosening the camshaft housing to the cylinder head retaining bolts.

•	Leave the 2 bolts loosely in place in order to hold the camshaft housing while separating the camshaft cover from the housing.

10. Remove the camshaft housing to the cylinder head retaining bolts.

Important: Tighten the bolts evenly in order to prevent the cover from binding on the dowel pins.

11. Push the cover off the housing by threading four of the housing to head retaining bolts into the tapped holes in the camshaft housing cover.
12. Remove the 2 loosely installed camshaft housing to head bolts.
13. Remove the cover and discard the gaskets.
14. Loosely reinstall one camshaft housing to cylinder head bolt in order to retain the housing during the camshaft and lifter removal.
15. Note the position of the chain sprocket dowel pin for reassembly.

Remove the camshaft being careful not to damage the camshaft or the journals.

Important: The valve lifters are not serviceable. Replace faulty valve lifters.

Coat the valve lifter with the camshaft and lifter prelube GM P/N 12345501 (Canadian P/N 992704), or the equivalent. If the new lifters are installed, add the engine oil supplement GM P/N 1052367 (Canadian P/N 992869), or the equivalent, to the engine oil.
16. Remove the valve lifters as follows:

•	Keep the lifters in order to reinstall the lifters to the original locations.

•	In order to minimize the lifter bleed down, perform the following procedure:

-	Store the lifters upside down, opposite of the installed position, on a level surface.

-	Store the lifters submerged in clean engine oil.

Important: Ensure that the alignment dowel pins are in the cylinder head prior to installing the camshaft housing.




17. Remove the camshaft housing and the gasket.

1. Install the camshaft housing to the cylinder head with a new gasket.

Sealer is unnecessary.

2. Loosely install on camshaft housing to the cylinder head bolt in order to hold the housing in place.

Important: Used lifters must be returned to the original position in the camshaft housing. If the camshaft is being replaced, the lifters actuated by the camshaft must also be replaced.

3. Install the lifters into the lifter bores.
4. Install the camshaft in the same position as when removed.

The timing chain sprocket dowel pin should be straight up and line up with the centerline of the lifter bores.

5. Install the new camshaft housing to the green colored camshaft housing cover seals and into the cover.

Sealant is unnecessary.

6. Remove the bolt holding the housing in place.
7. Apply the pipe sealant GM P/N 1052080 (Canadian P/N 10953480) or the equivalent to the camshaft housing and the cover retaining bolt threads.



8. Install the camshaft housing cover to the camshaft housing.




Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

Important: The top intake camshaft housing bolts are tightened to a different specification than the other camshaft housing bolts.

9. Using the J 36660-A Torque Angle Meter:

Tighten

•	Tighten the camshaft housing to cylinder head bolts to 15 N·m (11 lb ft) + 90 degrees.

•	Tighten the camshaft housing cover to camshaft housing bolts to 15 N·m (11 lb ft) + 30 degrees.

10. Install the timing chain housing and the timing chain. Refer to Timing Chain Housing Replacement .
11. Install the camshaft position sensor connector.
12. Install electrical to oil pressure sensor.

Important: When reinstalling the power steering pump, apply a 3 mm bead of GM P/N 12346286 (Canadian P/N 10953472) sealer or the equivalent to the joint at the end of the camshaft housing halves before the installation of the power steering pump and the pump face seal.




13. Install the power steering pump assembly.
14. Install ignition coil and module assembly. Refer to Ignition Control Module Replacement in Engine Controls.

Important: Do not compress the lifter plungers using a vise or other tool. This will cause more air to enter the lifter assembly and will take more time to bleed out once the lifters are installed.

15. If new lifters have been installed or the lifters bled down while the engine was disassembled, excessive lifter noise may be experienced. This is a normal condition and no engine damage is occurring. Use the following procedure to purge air from the lifters:

15.1.

Start the engine and allow the engine to warm up at idle for 5 minutes.

15.2.

Increase the engine speed to 2,000 RPM until the lifter noise is gone.

15.3.

Return the engine to idle for an additional 5 minutes or perform a road test.

16. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.