GM 19355205 Spark Plug Asm,Gasoline Engine Ignition

Resistor type, tapered seat spark plugs are used, with some applications using a platinum spark plug, usually designated by a 'P' suffix in the part number. Normal service is a mixture of idling, slow speed, and high-speed driving, with occasional intermittent high-speed driving needed for good spark plug performance. Worn or dirty spark plugs may operate satisfactorily at idling speed, but often fail at higher RPM. A typical spark plug consists of a metal shell surrounding a ceramic insulator, with a metal electrode extending downward through the center of the insulator. The spark plug does not produce a spark but provides a gap across which the current can arc. Spark plug heat range is the ability of the plug to dissipate heat. The general rule of thumb for choosing the correct heat range is: if most of your driving is long distance, high-speed travel, use a colder plug; if most of your driving is stop and go, use a hotter plug. A set of standard spark plugs usually requires replacement after about 30,000 miles (48,000 km), depending on your style of driving. When you're removing spark plugs, work on one at a time. Don't start by removing the plug wires all at once because, unless you number them, they may become mixed up. Check the plugs for deposits and wear. If they are not going to be replaced, clean the plugs thoroughly. Plugs can be cleaned on a spark plug cleaning machine, or you can do an acceptable job of cleaning with a stiff brush. Check spark plug gap before installation. The ground electrode must be parallel to the center electrode, and the specified size wire gauge must pass between the electrodes with a slight drag.

Worn or dirty spark plugs may operate satisfactorily at idling speed but often fail at higher RPM.

You should assess their accessibility, especially if the car has air-conditioning or power steering, as special tools may be necessary.

Always ensure spark plugs are tightened to the specified torque without over-tightening.