GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

Notice: Observe the following service precautions:

   • Allow the engine to cool before removing the spark plugs. Attempting to remove spark plugs from a hot engine can cause the spark plugs to seize. This can damage the cylinder head threads.
   • Clean the spark plug recess area before removing the spark plug. Failure to do so can result in engine damage due to dirt or foreign material entering the cylinder head, or in contamination of the cylinder head threads. Contaminated threads may prevent proper seating of the new spark plug.
   • Use only the spark plugs specified for use in the vehicle. Do not install spark plugs that are either hotter or colder than those specified for the vehicle. Installing spark plugs of another type can severely damage the engine.


    Object Number: 1774994  Size: SH
  1. Remove the intake manifold cover, if required. Refer to Intake Manifold Cover Replacement .
  2. Remove the air cleaner outlet duct, if required. Refer to Air Cleaner Outlet Duct Replacement .
  3. Remove the left side spark plug wires from the spark plugs, if required.

  4. Object Number: 1798989  Size: SH
  5. Remove the right side spark plug wires from the spark plugs, if required.

  6. Object Number: 1587748  Size: SH
  7. Remove the spark plugs from the engine.

Installation Procedure

Notice: It is important to check the gap of all new and reconditioned spark plugs before installation. Pre-set gaps may have changed during handling. Use a round wire feeler gauge to be sure of an accurate check, particularly on used plugs. Installing plugs with the wrong gap can cause poor engine performance and may even damage the engine.

Notice: Be sure plug threads smoothly into cylinder head and is fully seated. Use a thread chaser if necessary to clean threads in cylinder head. Cross-threading or failing to fully seat spark plug can cause overheating of plug, exhaust blow-by, or thread damage. Follow the recommended torque specifications carefully. Over or under-tightening can also cause severe damage to engine or spark plug.


    Object Number: 1587748  Size: SH
  1. Gap the NEW spark plugs. Refer to Ignition System Specifications .
  2. Notice: Refer to Fastener Notice in the Preface section.

  3. Install the NEW spark plugs.
  4. Tighten
    Tighten the plugs to 20 N·m (15 lb ft).


    Object Number: 1798989  Size: SH
  5. Install the right side spark plug wires to the spark plugs, if required.

  6. Object Number: 1774994  Size: SH
  7. Install the left side spark plug wires to the spark plugs, if required.
  8. Install the air cleaner outlet duct, if required. Refer to Air Cleaner Outlet Duct Replacement .
  9. Install the intake manifold cover, if required. Refer to Intake Manifold Cover Replacement .