The cylinder head contains the spark plugs and the equipment needed to change them will normally have a spark plug socket which fits into a ratchet, a number of extensions and a feeler gauge to measure and adjust the spark plug gap. As these engines are aluminum head cylinder-headed, tightening is to be done using a torque wrench. It would be better to buy the new spark plugs in advance, align them to the required distance and change one after another, being sure that you bought the right type of the spark plugs which depend on the engine type. It is best to leave the engine to cool, and meanwhile inspect the new plugs and determine whether they are defective or not, and also inspect with regard to gaps. The gap is checked by placing the relevant thickness gauge between the electrodes and making sure that the thickness gauge slides with a slight drag and any cracks in the plug body are also examined. The fender must be covered with a fender cover or a used blanket to avoid damage of the paint. The cylinders have one spark plug centrally located in the middle of the cylinder and the ignition coils are mounted over the spark plugs, directly above the ignition coils, remove the ignition coils out of the ignition plugs. Where possible, blow off the dirt using compressed air in the area of the spark plug, but precautions should be taken to avoid causing the debris to fall inside the cylinder by using eye protection. The spark plug socket can be used to remove the plug by turning it counterclockwise. Apply anti-seize compound to the threads of the new spark plugs in a light coating to avoid seizing in the aluminum head. To prevent cross-threading, simply slide a piece of rubber hose over the end of the spark plug, this helps keep the part of the spark plug in proper position with the hole and prevents the threading of the part should it start cross-threading. Install the spark plugs and screw them in the required tightening, and repeat the process with the rest of the plugs.