These engines have the spark plugs positioned at the engine head, and the materials needed to replace it often have a spark plug socket that can be attached to a ratchet, several extensions, and a gap gauge to check and adjust the gaps on the new plugs, where a torque wrench is often advised to tighten the fittings. It is also recommended to buy new plugs before hand, adjust them to correct spacing and change one at a time, making sure that the correct type of plug is bought to fit the type of engine. Ensure that the engine is completely cool before unscrewing any plugs to prevent any damage to the aluminum cylinder heads and in the meantime, inspect the new plugs on the openings and trie the gaps. This is checked by passing the proper-thickness gauge between the electrodes, making sure that it slides with a little drag; otherwise the side electrode can be changed and cracks in the porcelain insulator checked. On models with an engine cover, this is to be removed, and on certain engines individual
Ignition Coils might need to be accessed before the plugs. Assuming that there is some compressed air available, then clear out any dirt in the spark plug hole with the compressed air first and then then use a spark plug socket to unscrew the spark plug in the counterclockwise direction. Compare old spark plug to new ones to evaluate the running condition of the engine, add a small portion of the anti-seize compound to the threads of the new plug and screw it in until it is not possible to turn it by hand and then use a torque wrench or a ratchet to screw it in. A piece of rubber hose can be utilized to assist in threading the plug in, so that it does not cross-thread and break. In the case of coil-over plug, inspect the ignition coil prior to installation, and the same process should be repeated with rest of the spark plugs.