How Long Do Iridium Spark Plugs Last? (+4 FAQs)

How long do iridium spark plugs last?
And, is there a way to improve their lifespan?

Indeed, there is.

In this article, we’ll discover how long do iridium spark plugs last and the right way to make them last longer. We’ll also answer a couple of frequently asked questions about iridium spark plugs.

Let’s begin!

How Long Do Iridium Spark Plugs Last?

Generally, an iridium spark plug can last for 3000-4000 hours of engine runtime or up to 100,000 miles or more.

While an iridium spark plug is made to last longer than platinum or copper core spark plugs, the iridium plug isn’t made equal. Iridium spark plugs from various brands may have different life spans.

However, manufacturers recommend changing an iridium spark plug at fixed intervals regardless of the plug’s operating quality. This helps ensure that the plugs burn fuel optimally, offering better fuel efficiency and engine performance.

Let’s find out how long different categories of iridium spark plugs last.

1. Single Iridium Plugs

A single iridium spark plug has a fine-wire iridium center electrode and a traditional nickel alloy ground electrode usually found in conventional spark plugs (copper plugs).

While a typical iridium spark plug can last for 50,000-80,000 miles, manufacturers set different limits for these plugs based on driving conditions.

For example, NGK’s Iridium IX spark plugs claim a 40,000-50,000 miles life expectancy on an unaltered motor. Denso iridium spark plugs recommend getting a new Iridium Power Denso plug at 30,000 miles.

2. OE Iridium Long Life Spark Plugs

OEM long life spark plugs feature a center electrode with an iridium disc and a ground electrode with a platinum tip. Some long life iridium spark plugs have iridium on the ground electrode as well.

OE iridium spark plugs are usually recommended for specific engines and can last 80,000-120,000 miles. Popular ones include Bosch Double Iridium, AC Delco, Champion Iridium, NGK Laser Iridium, and Denso’s Long Life spark plugs.

3. Aftermarket Long Life Iridium Plugs

Aftermarket iridium spark plugs also feature a fine-wire iridium center electrode and platinum or iridium tipped ground electrode.

These plugs are as good as OE iridium plugs and can last for 100,000 miles under normal driving conditions. Some popular ones in this category include Champion Iridium, Denso Iridium TT, and the Autolite Iridium plug.

4. Iridium Racing Spark Plugs

You can find specialized racing plugs for high-performance engines. These feature an iridium center electrode and platinum ground electrodes. When installed on regular vehicles, they can last for a reasonably long time.

Popular ones in this category are Denso Iridium racing plugs, and a few NGK Iridium plugs.

While these are the general guidelines, you can do a couple of things at your end to make an iridium plug last longer.

Let’s find out how.

How To Make An Iridium Plug Last Longer?

Whether you own a Honda or Toyota, here’s what you can do to get the best performance from your spark plugs and make them last longer:

1. Pick The Right Iridium Plug

When getting a spark plug replacement, ensure that the new spark plug matches your vehicle’s heat range specifications. Heat range is the temperature range within which a spark plug can operate.

Your new plug should be hot enough to get rid of the carbon deposits, yet it shouldn’t cause pre-ignition or an explosion.

2. Avoid Using Anti-Seize

Using anti-seize can make it difficult to remove worn spark plugs from the cylinder head if they have been inside the combustion chamber for too long.

It increases the risk of tightening the plug during installation. This can break the spark plug or damage its threads during disassembly. It’s best to install a spark plug dry.

3. Don’t Wait Until The Last Mile

It can be hard to pull out an iridium plug once it crosses 150,000-200,000 miles. You’ll most likely end up with a broken spark plug.
It’s best to replace a spark plug before reaching the recommended limit.

Let’s look at some common spark plug questions next.

4 Iridium Spark Plug FAQs

Here are answers to some common iridium spark plug related questions:

1. Do Iridium Spark Plugs Ever Need To Be Changed?

It’s recommended to replace an old spark plug at 100,000 miles or earlier (as specified by the spark plug manufacturer) to maintain engine performance and fuel efficiency.

Even though your engine may continue to work just fine, you may experience reduced fuel economy due to inefficient fuel mixture combustion.

Moreover, you’ll have difficulty getting those plugs out of the cylinder head. Overuse and corrosion on spark plugs will most likely break or strip the plug on retrieval. And if the spark plug breaks off, leaving the tip inside the cylinder head, you’re looking at some costly combustion chamber repairs.

To avoid this, refer to your owner’s manual to know the intervals at which you should inspect and change spark plugs.

2. How Do I Know If My Spark Plug Needs Replacing?

A build-up of oil fouling and carbon on the electrode and threads or an increase in the spark plug gap means you have worn out spark plugs. However, these signs are only evident upon visual inspection.

Here are some other signs that call for a spark plug inspection and replacement:

Engine misfires
Backfiring
Ignition system startup problems
Vehicle not running at the usual speed
Rough idling

3. How Much Will An Iridium Spark Plug Replacement Cost?

An iridium spark plug can cost between $20-$100 each. You can expect to pay anywhere from $40-$350 as labor charges, depending on your area. The labor charges could also increase if the mechanic has to take out the intake manifold to access the worn spark plugs.

On average, spark plug replacement can cost you $100-$250 on the lower end to $250-$500 on the higher side (for a V6 engine).

4. How Are Iridium Plugs Better Than The Other Spark Plug Types?

The iridium spark plug is considered the most durable and long-lasting spark plug compared to the other types of spark plugs.

These include the:

1. Copper Spark Plug

Also known as the conventional spark plug, standard plug, or normal plug, a copper spark plug is the most common one found on the market. A standard copper plug has a copper core and nickel alloy coated center electrode.

The conventional spark plug with a copper core is cheaper than an iridium plug, with a maximum lifespan of 32,000 miles due to its low melting point.

2. Platinum Spark Plug

A platinum or double platinum spark plug (with platinum discs on both spark plug electrodes) is harder and more expensive than conventional spark plugs (copper). A platinum spark plug can last 100,000 miles.

However, iridium is much harder and stronger than platinum when handling the high voltage coming from an ignition coil through a spark plug wire.

Iridium plugs generally last longer than a regular platinum plug or double platinum (usually recommended for the waste spark distributor ignition system).

3. Silver Spark Plug

A silver spark plug has a silver-coated electrode tip. However, these are less durable than copper, platinum, or iridium and are not commonly found on vehicles.

Final Thoughts

Iridium spark plugs are the best for better fuel combustion, durability, and wear resistance. An iridium plug can last much longer than a copper plug or a platinum spark plug.

As for an iridium spark plug replacement — if you need help, contact AutoNation Mobile Service!

We’re a convenient mobile auto repair and maintenance solution with expert mechanics. They can inspect your old spark plug and, if needed, install a new spark plug on your car right in your driveway.

Fill up this form to get an accurate cost estimate for a spark plug replacement or other automotive repairs!