For 1990-2009 cars

Important:

• | Use this procedure only if the camshaft or lifters are going to be removed.

• | Read the entire procedure before removing the camshaft housing.

• | Replace the camshaft housing to cylinder head gasket any time the camshaft housing to cylinder head bolts are loosened or removed.

• | Ensure that the valve lifters are kept together and identified during disassembly. Do this in order to ensure that the valve lifters are installed in the original location.

Important: Use the reverse of the tightening procedure when loosening the camshaft housing to the cylinder head retaining bolts. Leave the bolts loosely in place to hold the camshaft housing while separating the camshaft cover from the housing.

1. Remove the camshaft housing cover to the camshaft housing retaining bolts.
2. Remove the remaining camshaft housing to the cylinder head retaining bolts.
3. Remove the camshaft sensor bolt.
4. Remove the camshaft sensor.

Important: Push the cover off of the housing. Remove the cover by threading four of the housing to head retaining bolts into the tapped holes in the camshaft housing cover.

Tighten the bolts evenly in order to prevent the cover from binding on the dowel pins.
5. Remove the loosely installed camshaft housing to head bolts.
6. Remove the camshaft housing cover. Discard the seals.
7. Loosely reinstall one camshaft housing to the cylinder head bolt in order to retain the housing during camshaft and lifter removal.
8. Remove the camshaft. Be careful not to damage the camshaft or journals.

Important: Keep the valve lifters in order so they can be reinstalled in the same location.

9. Remove the valve lifters.
10. Follow the below guidelines in order to minimize lifter bleed down:

• | Store the lifters upside down on a level surface. Keep the camshaft contact surface down.

• | The lifters can also be submerged in clean engine oil.

Important:

• | The valve lifters are not repairable. Replace the lifters if the lifters are faulty. Do not get prelube on the camshaft cover seals because the seals will swell.

• | Coat the lifter with Camshaft and Lifter Prelube GM P/N United States 12345501, GM P/N Canada 992704 or the equivalent before installation.

11. If new lifters are installed, add Engine Oil Supplement GM P/N United States 1052367, GM P/N Canada 992869 or an equivalent to the engine oil.
12. Remove the camshaft housing.
13. Remove the camshaft housing gasket.