GM 12681664
Spark Plug

Replace spark plugs by beginning with the removal of the intake manifold cover if required. Position each Spark Plug wire before removing the connection by twisting its Spark Plug boot 1/2 turn counterclockwise followed by lifting the heat shield gently with the Spark Plug boot removal tool (J 38491). Proceed to remove the air inlet grille once the step is finished. The process for removing Spark Plug Wires must repeat itself at the rear engine position. Use the specific tool to take out all spark plugs from the engine block. Step one of installation requires measuring the gap of new spark plugs before checking against the specified gap requirements for adjustment. Insert the spark plugs into their proper positions then tighten them to 15 n.m (11 lb ft). Return Spark Plug Wires to the rear spark plugs first followed by air inlet grille installation then proceed with sparking wires installation to front spark plugs if required. Place all intake manifold cover back into position if required.

Flash the ignition off before you remove the Ignition Coil while wearing safety glasses to protect your eyes but maintain caution regarding compressed air. Clean the Spark Plug recess area before maintenance to stop dirt or foreign material intrusion that might harm the engine and dirty the Cylinder Head threads leading to improper new plug seating. A thread chaser offers the best method to eliminate contaminants from threaded areas. Compressed air cleanup of the Spark Plug chamber will become essential after the engine has time to cool since rapid hot Spark Plug removal could lead to thread seizing damage of the Cylinder Head threads. Vehicle engine health relies on using spark plugs specified for the vehicle because different heat levels in plugs can cause serious damage to engine components. All new and reconditioned spark plugs must undergo gap testing with a round feeler gauge because handling can affect their original spacing. A Spark Plug should have exactly the same Spark Plug gap measurement as its original specification. Use a thread chaser to clean threads before installing the Spark Plug since improper thread placement or incomplete seating could cause overheating while allowing exhaust to escape through unscrewed threads which may also damage the threads. The technician should apply 20 n.m (15 lb ft) torque force when installing the Spark Plug with subsequent reinstallation of the Ignition Coil.

Propducers need to obtain Spark Plug boot removal tool (J 38491) as their first essential device for Spark Plug replacement. First untie the intake manifold cover according to necessity. Apply proper note-taking to record Spark Plug wire placement before moving to remove the wires from spark plugs at engine's front section. You must first twist each Spark Plug boot by 1/2 turn before removing it to gently lift the heat shield from the spark plugs using the Spark Plug boot removal tool (J 38491). The same wire removal procedure should be performed at the rear location of the engine. You should remove the spark plugs from the engine after all wires have been successfully taken off. Testing of new Spark Plug gap requirements starts by measuring the gap before any adjustments that might be needed to match specifications. This engine requires new spark plugs which you need to install according to a torque of 15 n.m (11lb ft). Reinstall the Spark Plug Wires to spark plugs located at both the rear and frontal areas of the engine before placing the intake manifold cover back on if it was disassembled.

Beginning the Spark Plug replacement process requires turning off the Ignition Switch followed by disassembly of the fuel injector sight shield. Start by removing the engine-based spark plugs along with disconnecting their Spark Plug Wires from the engine. A proper Spark Plug gap measurement should be taken before installation to verify the required specifications. Make adjustments to achieve the necessary gap. The installation torque for new cylinders should reach 27 nm (20 lb ft) but existing cylinders require a torque of 15 nm (11 lb ft). Plug the spark wires back in place before placing back the fuel injector shield.

Quality of the Spark Plug must be verified to ensure its correct installation because incorrect plugs will create driveability issues while heat range requirements prevent fouling caused by cold plugs or pre-ignition damage from hot plugs. Thoroughly check the terminal post while inspecting for any damage and verify its stability by twist and pull tests which must avoid post movement. The Spark Plug boot and recess area of the Cylinder Head should be checked for moisture while inspecting for boot damage as moist conditions can lead to arcing. Also check if electrical charge is crossing between the terminal post and ground which could cause flashover or carbon tracking in the insulator . Control a test for insulator cracks to prevent electrical charge from arcing through unproper holes (3, 4) while measuring the center to side electrode gap distance to guarantee proper functioning (4). The correct torque setting for the Spark Plug must be confirmed because both low and excessive torque affect performance through operational issues or insulator breakdown. Check for tracking signs at the insulator tip while inspecting both the side electrode for damage as well as the center electrode for looseness or damage with a rattling sound when shaken. Please check for contact between electrodes (3, 4) since deposits might eliminate the gap completely and review the electrodes (3, 4) for platinum pad integrity as well as excessive fouling materials. The Spark Plug recess area in the Cylinder Head requires inspection to determine if debris exists because both broken threads and contamination could prevent the plug from installing correctly. The Spark Plug reveals brown to grayish-tan coloration alongside minimal white debris under normal conditions while carbon buildup takes the form of dry fluffy black carbon deposits when the engine involves rich mixtures and leaking fuel injectors and high fuel pressure and restricted air filters and incorrect combustion and weak ignition systems and too much idling and improper Spark Plug gap. The spark intensity suffers from deposit fouling inflicted by oil together with coolant or specific additives yet most powdery deposits do not affect spark intensity if they do not solidify to cover the electrode.

Engine replacement starts with waiting for engine cooling to stop because sealing problems may occur when handling Cylinder Head threads. Thoroughly clean the Spark Plug recess space to stop debris from entering the Cylinder Head because this material can make the threads become contaminated resulting in improper Spark Plug seating. The engine faces severe damage when using spark plugs outside of the specified vehicle model. Start the procedure by detaching Spark Plug Wires from their positions on the spark plugs before you remove these plugs from the Cylinder Head. A round wire feeler gauge should be used to check gaps on newly installed or reconditioned spark plugs before mounting them as pre-adjusted gaps might have changed. Follow the gap specifications mentioned in ignition system specifications when dealing with spark plugs. The plug threads should enter the Cylinder Head smoothly until it reaches full seat position; use a thread chaser to clean threads when needed. It is important to follow recommended torque limits precisely because improper screw placement might result in overheating and exhaust leaks and thread damage to the system. First-time installation of spark plugs in new cylinder heads should have a torque specification of 20 n.m (15 lb ft) while all subsequent installations follow a torque value of 15 n.m (11 lb ft). The process ends with attaching the Spark Plug Wires to their fitting points on the spark plugs.

The start of Spark Plug replacement requires an off ignition and disconnection of the electronic ignition (EI) module harness connector. Detach the bolts holding the Ignition Coil housing then detach the housing from the engine. A 5/8 inch Spark Plug socket should be used to remove spark plugs while clearing the Spark Plug holes of water and debris before their removal. Use new spark plugs by avoiding anti-seize compound on threads but tighten them to 20 n.m (15 lb ft) while setting the correct 1.1 mm (0.45 in) gap. The Spark Plug boots should receive an application of dielectric compound while checking for possible corrosion. Fasten the Ignition Coil housing onto the cam cover through attachment bolts which should be tightened to 10 n.m (89 lb in). Connect the ei module harness connector by pushing down until it emits a click after which you should pull it back to verify connection.

The electronic ignition (EI) module harness' connection needs to be disconnected first followed by turning off the ignition when replacing spark plugs. First detach the ignition coil housing through its bolt structure then evacuate all fluid and debris away from the Spark Plug holes. The job requires a 5/8 inch Spark Plug socket for removing the plugs. Tighten the spark plugs to 20 n.m while setting them to 1.1 mm. Avoid using anti-seize compound since it might damage Cylinder Head threads if over-torqued. Using dielectric compound on the Spark Plug boots the technician inspects for corrosion followed by an installation of the ignition coil housing onto the cam cover which requires bolt tightening at 10 n.m (89 lb in). Hook up the ei module harness connector by allowing it to click and retreat to verify proper connection.

Engine replacement should begin with waiting until the motor has cooled down because hot temperatures cause the threads to stick and harm the Cylinder Head. Clearing the Spark Plug recess area from contamination will prevent problems with new plug installation. Spark plugs suitable only for the vehicle need installation since different types create severe harm to the engine. When replacing spark plugs of the engine right bank, rotate the engine for better access to the workspace. To commence the procedure first detach both the Spark Plug Wires and then remove the spark plugs from the engine compartment. Spark Plug installation requires gauging the gap precisely with a round wire feeler gauge to maintain the specified dimensions since the pre-set gaps modify while working on the parts. Insert spark plugs into the engine while maintaining 20 n.m (15 lb ft) torque if you install new cylinder heads. Otherwise tighten the plugs to 15 n.m (11 lb ft). Make sure both retainers have proper thread engagement and full seat positioning. A thread chaser (J 41131) should be used for any necessary.thread-cleaning. To complete the installation point the following steps in sequence: mount the Spark Plug Wires then unfasten the engine tilt strap (J 41131) and return the engine to normal position followed by engine mount strut installation.

Verify that the proper Spark Plug is installed to prevent driving problems and ensure that it has a suitable heat range which will help avoid plug fouling or pre-ignition failure from using a plug with poor heat resistance. The terminal post needs an inspection for damage verification while testing its stability through twisting and pulling motions. Successfully steady base position verifies its safety. The insulator needs inspection for flashover or carbon tracking since electrical charge movement from terminal post to ground can cause problems while looking for boot damage alongside moisture in the Cylinder Head recess. Verify the insulator has no cracks that would allow arcing instead of electrode contact by examining it (3, 4). Also check that the gap between center electrode and side electrode matches design specifications to ensure proper performance. Professional technicians should check the correct torque setting for spark plugs because low torque generates operational problems but high torque can break the insulator. The insulator tip should be checked for tracking indications and both the side and center electrodes need inspection for wear, breakage and looseness or damage which produces a rattling sound when shaken. Verify the electrodes (3, 4) have no bridge formation from deposits and inspect platinum pads on these electrodes (3, 4) when present. No debris should exist in the recess area of the Spark Plug because any damage or dirt can stop the plug from seating properly when you put it in. The visual inspection of the spark plugs reveals a brown to grayish-tan coloration with minimal white particles under normal conditions but carbon fouling appears as dry black carbon due to multiple factors consisting of rich fuel mixtures, fuel injector leakage, high fuel pressure or faulty air filters or incorrect combustion, reduced ignition voltage, weak coils, worn ignition wires, improper Spark Plug gap or prolonged idling. Electrode spark intensity reduces when deposit fouling material from oil, coolant or additives creates either surface glazing or forms a film over the electrode.

The first step to replace a Spark Plug consists of removing the suitable Spark Plug wire boots which requires rotating each boot 1/2 turn while only grasping the boot itself or using the appropriate tool. The Spark Plug requires 1 to 2 turns of loosening before clearing away surrounding dirt by brushing or air blast. Put each plug into its own marked tray during the removal process according to cylinder number. The check and modification process of the Spark Plug gap must follow engine mechanical specifications. Follow this procedure for installing your Spark Plug to the Cylinder Head using hand pressure until it reaches a torque of 15 nm (11 lb ft). The inside of each Spark Plug wire boot needs dielectric grease gm p/n 12345579 (Canadian P/N 10953481) applied before putting back the appropriate plugs.

Verify that the spark plug gap matches the specification using a round feeler gauge.

Repeat the process for the spark plug wires at the rear of the engine.

Check the gap with a round feeler gauge, as pre-set gaps may change during handling.

Excessive idling or slow speeds can prevent normal combustion deposits from burning off.

Turn the ignition OFF and remove the ignition coil.

Ensure the engine is cool before beginning.

Install the spark plugs into the engine, tightening them to 15 N.m (11 lb ft).

Twist the spark plug boot 1/2 turn.

Dirty or damaged threads can prevent proper seating during installation.

A thread chaser may be used for this purpose.

Gap the spark plugs to the specifications using a round wire feeler gauge for accuracy.

Only the specified spark plugs for the vehicle, as using plugs that are hotter or colder can severely damage the engine.

Tighten them to 27 N.m (20 lb ft).

Remove the spark plugs from the engine.

Examine the spark plug boot for damage and the spark plug recess area of the cylinder head for moisture, such as oil, coolant, or water.

Use the Spark Plug Boot Removal Tool (J 38491).

To avoid driveability issues and to verify that it has the appropriate heat range to prevent fouling from a colder plug or pre-ignition damage from a hotter plug.

Ensure the plugs thread smoothly and are fully seated; use a thread chaser if necessary to clean the threads.

Install the spark plugs into the cylinder head, ensuring they thread smoothly and are fully seated; use a thread chaser if necessary.

To prevent damage to the cylinder head threads.

Gap the spark plugs to the specifications outlined in Ignition System Specifications, checking the gap of all new and reconditioned plugs with a round wire feeler gauge.

Only the specified spark plugs for the vehicle, as using plugs that are hotter or colder can severely damage the engine.

To avoid dirt entering the cylinder head, which can contaminate the threads and prevent proper seating of the new spark plugs.

Ensure the plug threads smoothly into the cylinder head and is fully seated, using a thread chaser if necessary to clean the threads.

Check for damage, ensuring it is not bent or broken, and test its stability by twisting and pulling; it should remain stationary.

To avoid dirt or foreign material entering the cylinder head, which can contaminate the threads and hinder proper seating of the new spark plugs.

Use a thread chaser (J38491) to clean any contamination.

Check for damage, ensuring it is not bent or broken, and test for looseness by twisting and pulling.

To avoid contamination that could affect the seating of new plugs.

Ensure the engine is cool to prevent seizing and damage to the cylinder head threads.

It can prevent normal combustion deposits from burning off.

Only use the specified spark plugs for the vehicle, as using incorrect types can severely damage the engine.

Tighten the spark plugs to 15 N.m (11 lb ft).

To avoid dirt contamination, which can lead to engine damage and improper seating of new plugs.