How Often Should I Have My Spark Plugs Replaced?
An internal combustion engine needs three things to live up to its namesake: air, fuel, and spark. Spark plugs take care of that last item by generating a well-timed electrical current, which in turn ignites the gas and fuel mixture in the cylinders.
Like any other car part, spark plugs will eventually wear out and require replacement. Read on to learn more about changing spark plugs, including how often it should be done.
Why Replace Spark Plugs in the First Place?
Considering what goes on inside a typical engine, spark plugs live a pretty tough life. Because of that, spark plugs are designed with durability and longevity in mind. Nevertheless, spark plugs experience a wide range of wear and tear throughout their life.
Worn-out electrodes are the most common form of wear and tear seen on spark plugs. They’re also a sure-fire sign that your spark plugs have been installed for too long and need replacement ASAP. Spark plugs can also have their lives cut short by the following:
• Excessive carbon buildup due to an overly-rich fuel/air mixture or excessive idling
• Oil deposits caused by worn pistons or valve guides
• Severely burnt or eroded electrodes because of cooling system problems or pre-ignition
• Broken electrodes due to using the wrong spark plugs or improperly gapped plugs
It comes as no shock that worn-out spark plugs can do a number on your engine. Some of the more common vehicle symptoms caused by bad spark plugs include:
• Rough engine idle
• Knocking and pinging under load
• Poor fuel economy
• Poor acceleration
• No start or sluggish start
If your vehicle exhibits any of the above issues, then it’s time to have your spark plugs replaced regardless of mileage.
When and How Often to Replace Spark Plugs
You won’t need to change your spark plugs is often as you do your engine oil or coolant. In fact, modern spark plugs are designed to last far longer than most other engine components. It’s not unusual for spark plugs to last over 100,000 miles, which coincidentally is the standard replacement milestone for most vehicles.
How often you’ll need to replace your spark plugs depends mainly on your manufacturer’s recommendations, but also on a number of other factors. Spark plugs with platinum and iridium electrodes can go significantly longer between changes than plugs with traditional copper electrodes. Spark plug replacement intervals can also vary among vehicle models, engine types, and even duty cycles. A vehicle constantly used for towing may need its spark plugs changed sooner than one used exclusively for everyday commuting.
Fortunately, you can find this information in your vehicle owner’s manual under the regularly scheduled service section. You’ll also find info on a variety of other services, including oil changes, engine coolant changes, and more.
Even if your vehicle is in perfect running condition, it’s a good idea to check your spark plugs every so often. You can have your mechanic inspect the spark plugs during your next major tune-up service. If you prefer to check them yourself, you should do so at least every 30,000 miles.
If you aren’t sure when your spark plugs were last changed, go ahead and have them replaced. Doing so will give you greater peace of mind about your vehicle, plus you’ll be certain that it was serviced properly and that it’s good to go until the next scheduled tune-up.
Replace a Few or Replace Them All?
As a general rule, you’ll want to replace all of the spark plugs at the same time. Doing so not only guarantees consistent performance, but you won’t have to worry about older spark plugs failing or having to redo the entire spark plug replacement process.
Nevertheless, it’s not uncommon for people to replace only a single cylinder bank’s worth of spark plugs. Some engine designs, most notably transverse-mounted V6 and V8 engines, are notorious for having hard-to-reach spark plugs. Unfortunately, these half measures can result in your engine not running as well as it should.
It’s also not uncommon to inspect spark plugs and find only one or two that are in bad shape. In cases like these, you should have your mechanic troubleshoot and pinpoint the underlying problem before replacing all of the plugs.
