GM 12681657
Spark Plug

Wear safety glasses when removing the Ignition Coil(s) then handle with caution near compressed air. Thoroughly clean the Spark Plug recess zone to stop contaminants from getting into the Cylinder Head because such material might harm the engine or ruin the Cylinder Head threads thus blocking proper insertion of the new plug. Use a thread chaser (Tool Required: You must clean threads with a thread chaser (Tool Required: Thread Chaser). Apply compressed air to blow out debris in the Spark Plug hole after checking that the engine temperature is safe because hot engines can seize threads and harm the Cylinder Head. Next, remove the Spark Plug. Check the vehicle specifications to match new spark plugs with the designated type because improper plug selections will damage the engine critically. All new and reconditioned spark plugs require gap measurement through a round feeler gauge for accuracy because handling can affect pre-set gaps. The opened gap needs to align with the manufacturer's recommended Spark Plug gap requirements. Complete thread insertion should happen without any resistance while seated fully in the Cylinder Head. When needed use a thread chaser to prevent cross-threading and overheating problems during the installation process. After positioning the Spark Plug properly install it keeping torque at 20 n.m (15 lb ft) while also reinstalling any necessary ignition coils.

The first procedure when replacing a Spark Plug should be removing the Ignition Coil from the engine. Concrete measures must be taken to clear the Spark Plug recess of dirt since unrestrained debris entry into the Cylinder Head can harm the engine and contaminate the Cylinder Head threads thus preventing proper plug installation; utilize a thread chaser to purge thread contaminants followed by compressed air cleaning of the Spark Plug cavity. Wait for the engine to cool down until you remove the spark plugs because working on hot metal might damage the Cylinder Head threads by gripping plug threads. The installation of new spark plugs requires using only the specified plugs for the vehicle because using plugs with extreme temperature differences can harm the engine profoundly. All new and reconditioned spark plugs need to go through a gap check with a round feeler gauge to prevent engine performance issues or damage that occurs from wrong gaps. When installing the Spark Plug let the threads glide smoothly into the Cylinder Head until the plug reaches complete seat position; a thread chaser helps clean threads when the plug shows signs of cross-threading or improper installation to avoid overheating and exhaust blow-by and thread damage. Finally, fit the Spark Plug into place before tightening it to 20 n.m (15 lb ft) then reinstallation of ignition coils.