Hot Spark Plugs vs. Cold Spark Plugs

Not all spark plugs are created equal. Some spark plugs are made to burn hotter than others. Making sure that you install the right spark plugs can make a critical difference in the way your engine performs.  Using spark plugs that burn too hot for your particular engine can result in pre-detonation and cause your engine to overheat. But if your spark plugs burn too cold, your engine may perform sluggishly and you can end up with carbon fouling requiring you to clean or replace your spark plugs.

Don't let this happen to your spark plugs! Make sure you get the right hot or cold spark plug for your engine based on its model and use.

Spark plugs work by forcing electricity to arc across a gap, much like a bolt of lightning arcs from a cloud to the ground. A high voltage – anywhere from 40,000 to 100,000 volts – is needed to create a strong enough spark to ignite the fuel/air mixture and start your engine. All spark plugs feature ceramic inserts designed to insulate the high voltage at the electrode tip, where it can jump the gap and be directed into the engine’s cylinder. The resulting heat also helps to burn excess fuel and carbon deposits from the plug’s electrode.

Hot spark plugs feature a ceramic insulator designed with a smaller contact area surrounding the metal electrode to reduce heat transfer and keep the spark plug tip insulated. Cold spark plugs have a larger contact area and transfer more heat away from the spark plug tip. Because ceramic is such a poor conductor of heat, these spark plugs run cooler. Manufacturers specify a spark plug’s heat range using numbers but always ask before you buy as differing brands may use larger or smaller numbers to indicate a specific temperature range.

For many years, auto makers and mechanics recommended hot spark plugs for vehicles that primarily were driven slowly and for short distances, and cold spark plugs for automobiles driven on long distances and sustaining high speed highway use. Today, car and truck fuel/air mixtures and cylinder temperatures are electronically maintained within a much narrower range than before, primarily in an effort to minimize emissions. So, the practice has become a bit obsolete except when it comes to high performance race car engines, boat motors and truck engines. Because these engines generate crazy high heat, they often require colder spark plugs to keep the fuel/air mixture from igniting before the spark fires.

The best way to make sure you are using the right spark plug for your vehicle’s engine, based upon its primary use, is to check your vehicle owner’s manual. You also can find the right E3 spark plug for your car, truck, boat, power sports or lawn & garden equipment engine by checking our online interactive catalog.