GM 12681662
Spark Plug

The first step to replace spark plugs requires waiting for engine cool-down to stop potential seizure that would damage Cylinder Head threads. The Spark Plug recess area requires cleaning to stop foreign materials from entering the Cylinder Head because this contamination will block new Spark Plug threading and prevent a proper fit. The specified spark plugs must be employed exclusively because alternative temperature range plugs will lead to serious engine damage. Proceed with the removal of the air cleaner outlet duct and intake manifold cover then disconnect the Spark Plug Wires from the spark plugs on both the left and right sides. A round wire feeler gauge should be used to check the gap of both new and reconditioned spark plugs since their pre-set gaps could have changed from handling. Follow ignition system specifications to set gap distance for new spark plugs before installation with torque to 15 n.m (11 lb ft). After attaching both Spark Plug Wires reinstall the intake manifold cover before putting on the air cleaner outlet duct.

One should start the Spark Plug replacement process only when the engine has cooled down because cold temperatures prevent thread damage to the Cylinder Head. Wipe down the Spark Plug recess completely to keep dirt particles from the Cylinder Head where they might damage the threads needed for Spark Plug installation. Installing spark plugs that differ from the specified ones will cause severe damage to the engine. To reach the left bank spark plugs the engine needs to be rotated followed by removing the Spark Plug Wires and the spark plugs from the engine. The specifications determine the correct Spark Plug gap installation requires and you should use round wire feeler gauges especially for used plugs because improper gap settings may result in engine problems or damage. The installation procedure requires Spark Plug torque to 20 n.m (15 lb ft) for fresh cylinder heads but only 15 n.m (11 lb ft) for used heads using a thread chaser to clean and ensure proper thread seating. Take care to avoid both cross-threading and failing to fully seat spark plugs because such errors might lead to overheating or exhaust blow-by or thread breakage. The recommended torque values must be followed precisely to prevent severe equipment breakdown. After installing the Spark Plug Wires you should put back the engine to its initial position.

Start the Spark Plug replacement process only when the motor has cooled down to protect both the engine threads and stop them from seizing. Chasing dirt away from the Spark Plug recess will prevent it from contaminating the Cylinder Head and causing unsatisfactory new plug installation. The vehicle requires its precise spark plugs because engine damage occurs when replacing them with plugs having different heat levels. Start the procedure by detaching the air cleaner outlet duct followed by removing the intake manifold cover when they exist. The left Spark Plug Wires should be disconnected then engine rotation may be needed for proper access when removing right Spark Plug Wires and the actual spark plugs themselves. A round wire feeler gauge should be used to check the gap in new and reconditioned spark plugs during their installation because pre-installed gaps might have changed since manufacturing. The installer should first gap the new spark plugs according to ignition system specifications before installing them with torque set to 15 n.m (11 lb ft). After positioning the engine at its initial setting reinstall the Spark Plug Wires on the right-hand side and proceed with reconnecting the plug wires from the left side. Reinstall the intake manifold cover with the air cleaner outlet duct after both components were previously unbolted.

Use a round wire feeler gauge to check the gap of all new and reconditioned spark plugs, as pre-set gaps may have changed.

Apply dielectric compound to the spark plug boots, checking for any corrosion.

Ensure the spark plug gap is set to 1.06 mm (0.042 in) before reinstalling the ignition coil(s).

Loosen the spark plug 1 or 2 turns.

Remove the ignition coil(s) and clear any water or debris from the spark plug holes.