How Long Do Iridium Spark Plugs Last? [Explained]

It’s always worthwhile to know about the longevity of your car spark plugs. Iridium spark plugs being the most looked upon can last about 3000 to 4000 hours with seamless performance of the engine runtime up to 100, 000 miles or more.  

It is important to note that iridium spark plugs last longer than platinum or copper core spark plugs but the life span may vary depending on different spark plugs.

If you are about to choose iridium spark plugs for your vehicle, this article will help you to understand its durability and a lot more. Read on!

Life Span of Different Iridium Spark Plugs

Regardless of the iridium spark plug life span (3000-4000 hours) you should change them after the recommended time that the manufacturer tells you. This ensures the best performance and the smooth car ignition without any possible defect during the drive. Moreover, if the performance of spark plug is ideal you won’t have to face the irregularity of fuel burning.

Below is the ideal lasting time of different types in iridium spark plugs.

1. Single Iridium Plugs

In an iridium spark plug, there are fin-wired centered electrodes and a regular nickel alloy ground electrode that’s usually in the copper plugs. 

So the single iridium spark plug lasts about 50,000-80,000 miles but different manufacturers have their dedicated limit for that in which the driving approach of the vehicles matters the most. NGK’s Iridium IX spark plug has 40, 000-50,000 miles of longevity and Denso offers 30,000 miles.

2. Aftermarket Long Life Iridium Plugs

The manufacturing design of these plugs resembles single iridium spark plugs. The life-span is about 100,000 miles provided you drive normally. The most trusted ones in aftermarket iridium spark plugs are Champion Iridium, Denso Iridium TT, and the Autolite Iridium plug. 

3. Iridium Racing Spark Plugs

Iridium racing spark plugs are also found in performance with long-time durability. They have iridium centered electrodes and platinum ground electrons. In this category, the papules are Denso Iridium racing plugs, and a few NGK Iridium plugs.

4. OE Iridium Long Life Spark Plugs

OEM plugs have the enter electrode with an iridium disc and a ground electrode with a platinum tip. Therefore, they generally last about 80,000-120,000 miles and work for dedicated car engines. 

The most usable OEM spark plugs are Bosch Double Iridium, AC Delco, Champion Iridium, NGK Laser Iridium, and Denso.

Here is a quick visual info!

Iridium Spark PlugsLife Span (Avg.)
Single Iridium Plugs  50,000-80,000 miles
OE Iridium Long Life Spark Plugs 80,000-120,000 miles
Aftermarket Long Life Iridium Plugs 100,000 miles
Iridium Racing Spark Plugs3000-4000 hours

Add more Life to Iridium Spark Plugs

Luckily, adding the durability of the iridium spark plugs is in your hand. The tips are easy to apply and testified if you have any doubts regarding the outcome.

  • Keep the plugs replaced when needed. This is because once the iridium spark plug reaches beyond 150,000-200,000 miles you’ll have a hard time replacing them. So replace them when needed if you want to add more life to them.
  • Choose the right iridium plug that matches with your vehicle heat range specification. Heat range tells you how much heat a spark plug can bear.
  • Don’t use anti-seize because it makes removing worn-out plugs from the cylinder head a challenge. Also there is tightening risk which can damage or even break the plugs. So always install dry spark plugs.


Is iridium spark plug expensive?

Typically, iridium spark plug is available between the ranges of $20 to $100 (on each). However the cost will hike when you add the installation charges to that since the mechanic has to take out the older ones to install the newer plugs.

The spark plug replacement charges are $100 to $250 on the lower end to $250 to $500 on the higher side (if your car has a V6 engine). 

What are the signs of a bad spark plug?

The most common signs of a poor spark plug are:

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

Read Also: How to Tell If a Spark Plug Is Bad


Spark plugs make sure your vehicles run smooth and its ignition is just on-time. Therefore, always keep an eye on its durability performance. If you see any worn-out or detective appearance on them in any way, it’s best to replace them before it’s too late.

Iridium spark plugs are the best among the rest if you put more miles/hours on the engine but if you don’t replace them once they cross the limit, you will likely face malfunction in the car starting.

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