GM Service Manual Online
For 1990-2009 cars only

Spark Plug Replacement 3.5L Twin Cam V6 LX5

Removal Procedure

Tools Required

J 43094 Spark Plug Boot Puller

  1. Turn OFF the ignition switch.
  2. Remove the ignition coil assembly. Refer to Ignition Coil Replacement in Engine Controls - 3.5L.
  3. Use the J 43094 in order to remove the spark plug boots from the spark plugs.

  4. Object Number: 289889  Size: SH

    Notice: Allow the engine to cool before removing the spark plugs. Attempting to remove the spark plugs from a hot engine may cause the plug threads to seize, causing damage to cylinder head threads.

    Notice: Clean the spark plug recess area before removing the spark plug. Failure to do so could result in engine damage because of dirt or foreign material entering the cylinder head, or by the contamination of the cylinder head threads. The contaminated threads may prevent the proper seating of the new plug. Use a thread chaser to clean the threads of any contamination.

  5. Remove the spark plugs from the engine.

Installation Procedure

    Notice: 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.

    Notice: Check the gap of all new and reconditioned spark plugs before installation. The pre-set gaps may have changed during handling. Use a round feeler gage to ensure an accurate check. Installing the spark plugs with the wrong gap can cause poor engine performance and may even damage the engine.

  1. Measure the spark plug gap on the spark plugs to be installed. Compare the measurement to the gap specifications. Refer to Spark Plug Usage . Correct as necessary.

  2. Object Number: 289889  Size: SH

    Notice: Be sure that the spark plug threads smoothly into the cylinder head and the spark plug is fully seated. Use a thread chaser, if necessary, to clean threads in the cylinder head. Cross-threading or failing to fully seat the spark plug can cause overheating of the plug, exhaust blow-by, or thread damage.

    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.

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

  5. Install the spark plug boots to the ignition coil assembly.
  6. Install the ignition coil assembly. Refer to Ignition Coil Replacement in Engine Controls - 3.5L.

Spark Plug Replacement 3800 V6 L36

Removal Procedure

Tools Required

J 38491 Spark Plug Heat Shield Removal Tool

  1. Turn OFF the ignition switch.

  2. Object Number: 47611  Size: SH
  3. Disconnect the plug wires from the spark plugs. Refer to Spark Plug Wire Harness Replacement .
  4. Notice: Clean the spark plug recess area before removing the spark plug. Failure to do so could result in engine damage because of dirt or foreign material entering the cylinder head, or by the contamination of the cylinder head threads. The contaminated threads may prevent the proper seating of the new plug. Use a thread chaser to clean the threads of any contamination.

  5. Remove the spark plugs from the engine.

Installation Procedure

    Notice: 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.

    Notice: Check the gap of all new and reconditioned spark plugs before installation. The pre-set gaps may have changed during handling. Use a round feeler gage to ensure an accurate check. Installing the spark plugs with the wrong gap can cause poor engine performance and may even damage the engine.

  1. Measure the spark plug gap on the plugs to be installed. Compare to gap specification given in Spark Plug Usage . Correct the gap if necessary.
  2. Notice: Be sure that the spark plug threads smoothly into the cylinder head and the spark plug is fully seated. Use a thread chaser, if necessary, to clean threads in the cylinder head. Cross-threading or failing to fully seat the spark plug can cause overheating of the plug, exhaust blow-by, or thread damage.


    Object Number: 47611  Size: SH
  3. Install the spark plugs to the engine.
  4. Tighten
    Tighten the spark plugs to 15 N·m (11 lb ft).

  5. Connect the spark plug wires to the spark plugs in the proper position. Refer to Spark Plug Wire Harness Replacement .