For 1990-2009 cars

### Exhaust Camshaft Installation

1. Install the hydraulic lash adjusters into their bores in the cylinder head. Apply lubricant GM P/N 12345501 (Canadian P/N 992704), or equivalent.
2. Lubricate the valve tips with GM P/N 12345501 (Canadian P/N 992704), or equivalent.

Note: Used roller followers must be returned to the original position on the camshaft. If the camshaft is being replaced, the roller followers actuated by the camshaft must also be replaced.

3. Position the roller followers on the tip of the valve stem and on the lash adjuster. Apply lubricant GM P/N 12345501 (Canadian P/N 992704), or equivalent.
4. When installing camshafts, ensure the intake camshaft notch is in the 5 o'clock position (2) and the exhaust camshaft notch is in the 7 o'clock position (1). The number 1 piston should be at top dead center (TDC), crankshaft key at 12 o'clock.
5. Set the exhaust camshaft on top of the roller followers in the camshaft bearing journals. Lubricate with GM P/N 12345501 (Canadian P/N 992704), or equivalent.
6. Rotate the oil seal in the groove of the number one camshaft journal so the split line (1) is at approximately the 12:00 position before installing the camshaft caps.
7. Install the exhaust camshaft with the notch on the front (1) at approximately the 7 o'clock position.
8. Install the camshaft caps and hand start the camshaft cap bolts.

Caution: Refer to Fastener Caution in the Preface section.

9. Lubricate and tighten the camshaft cap bolts in increments of 3 turns until they are seated. Tighten the camshaft caps to 10 N·m (89 lb in).

### Intake Camshaft Installation

1. Install the hydraulic lash adjusters into their bores in the cylinder head.
2. Lubricate the hydraulic lash adjusters with GM P/N 1234550 (Canadian P/N 992704), or equivalent.
3. Lubricate the valve tips.

Note: Used roller followers must be returned to the original position on the camshaft. If the camshaft is being replaced, the roller followers actuated by the camshaft must also be replaced.

4. Position the roller followers on the tip of the valve stem and on the lash adjuster. Lubricate roller followers with GM P/N 12345501 (Canadian P/N 992704), or equivalent.
5. Ensure the intake camshaft notch is in the 5 o'clock position (2) and the exhaust camshaft notch is in the 7 o'clock position (1). The number 1 piston should be at top dead center (TDC), crankshaft key at 12 o'clock.
6. Set the intake camshaft on top of the roller followers in the camshaft bearing journals. Lubricate with GM P/N 12345501 (Canadian P/N 992704), or equivalent.
7. Rotate the oil seal in the groove of the number one camshaft journal so the split line (1) is at approximately the 12:00 position before installing the camshaft caps.

Note: The number 1 cylinder must be at top dead center (TDC), crankshaft keyway at the 12 o'clock position.

8. Install the intake camshaft with the notch on the front at approximately the 5 o'clock position (2).
9. Install the camshaft caps and hand start the camshaft cap bolts.
10. Tighten the camshaft cap bolts in increments of 3 turns until they are seated. Tighten the camshaft caps to 10 N·m (89 lb in).
11. Apply a 3.5 mm bead of sealer GM P/N 12378521 (Canadian P/N 88901148) to the cylinder head to number 6 camshaft cap mating surface.
12. Install the number 6 rear camshaft cap. Tighten the number 6 rear camshaft cap to 10 N·m (89 lb in).
13. Install the rear cylinder head opening plate and bolts and tighten to 10 N·m (89 lb in).