A Guide to Spark Plug Replacement for the 2015-2024 Mazda 3 Sport
Keep your Mazda 3's Skyactiv engine running smoothly with the right spark plugs.
- The recommended replacement interval is 75,000 miles.
- NGK is the OEM supplier; using their aftermarket Iridium plugs is a reliable and cost-effective choice.
- This is a very easy DIY repair that requires basic tools and can be done in under an hour.
- Avoid purchasing spark plugs from Amazon or eBay due to the high risk of counterfeit parts.
Symptoms of Failing Spark Plugs
When spark plugs wear out, your car will usually let you know. The signs can start small but will get worse over time. Ignoring them can lead to more expensive repairs down the road.
- Rough Idle: You may feel shaking or vibration when the car is stopped but the engine is running. Some owners report a knocking or ticking sound.
- Poor Acceleration: The car may feel sluggish or slow to respond when you press the gas pedal.
- Reduced Fuel Economy: If you notice you're filling up your gas tank more often, failing spark plugs could be the cause. A weak spark means the engine isn't burning fuel efficiently.
- Engine Misfires: A misfire is when a cylinder fails to ignite the fuel mixture correctly. It can feel like a hesitation or stumble from the engine and will often trigger the Check Engine Light.
- Difficulty Starting: Worn plugs can make it harder for the engine to start, especially in cold weather.
Choosing the Right Aftermarket Spark Plug
When it comes to spark plugs for your Mazda 3, you have options. The original parts are excellent, but high-quality aftermarket plugs can offer the same performance for less money.
OEM vs. Aftermarket Quality
The Original Equipment Manufacturer (OEM) spark plugs for the 2015-2024 Mazda 3 are made by NGK, and sometimes Denso. These are typically high-quality Iridium spark plugs designed for a long life. Aftermarket brands like NGK sell the exact same plug without the Mazda logo on the box, often for a lower price. For this specific vehicle, sticking with the OEM manufacturer (NGK or Denso) is highly recommended by mechanics and experienced owners.
Beware of Counterfeits
🎬 Watch: How to spot fake NGK spark plugs before installing them.There is a major issue with counterfeit spark plugs from top brands like NGK and Denso being sold on sites like Amazon and eBay. These fake plugs can cause poor performance and even engine damage. To be safe, purchase your spark plugs from a reputable auto parts store or a trusted online retailer.
Brand Tiers for Your Mazda 3
- Tier 1 (Recommended): NGK
As the OEM supplier, NGK is the safest and most recommended choice. Their Laser Iridium and Iridium IX plugs are considered the factory equivalent and will provide reliable performance and longevity. NGK's newer Ruthenium plugs are also an excellent, modern option. - Tier 2 (Use with Caution): Bosch
While Bosch is a major, reputable brand, owner experiences are mixed for Japanese vehicles like Mazda. Some forum discussions, though occasionally dated, report issues like misfires when using Bosch plugs in engines designed for NGK or Denso plugs. While many use them without problems, it's a slight gamble compared to sticking with the OEM brand. - Tier 3 (Economy Choice): Champion
Champion plugs are a well-known budget option. However, there is very little information from Mazda 3 owners recommending them. For a sensitive, high-compression engine like the Skyactiv, it is generally advised to spend a few extra dollars on the OEM-spec NGK plugs to avoid potential performance issues.
Known Issues, Recalls, and TSBs
There are no active recalls for spark plugs on the 2015-2024 Mazda 3. However, two Technical Service Bulletins (TSBs) are relevant for owners experiencing misfires:
- TSB 01-012/19: This bulletin addresses engine misfires (codes P0300-P0304) that can be caused by carbon buildup on the intake valves. The repair procedure involves removing the spark plugs to perform a decarbonization service. This means a misfire might not be the plug's fault.
- TSB 01-005/20: This document notes that water entering the spark plug wells can affect ignition coil performance and cause driveability problems. If you find water when changing your plugs, this could be the root cause of your issue.
DIY Installation
🎬 See this step-by-step walkthrough for replacing plugs on your Mazda 3.Replacing the spark plugs on a Mazda 3 with a 2.0L or 2.5L Skyactiv engine is a very simple DIY job that takes less than an hour. The plugs are located right on top of the engine, easily accessible by removing the plastic engine cover and four ignition coils. You only need basic hand tools, including a ratchet, an 8mm socket, and a 14mm spark plug socket.
Frequently Asked Questions
How often do I need to replace the spark plugs?
Mazda's official maintenance schedule recommends replacing the spark plugs every 75,000 miles (120,000 km).
Do I need to gap the new spark plugs?
No. High-quality Iridium and Ruthenium plugs from brands like NGK come pre-gapped from the factory. Attempting to gap them can damage the fine, brittle electrode. You should only verify the gap is correct, not change it.
Should I replace the ignition coils at the same time?
It is not necessary. Unlike spark plugs, ignition coils are not a routine maintenance item. You should only replace an ignition coil if it has failed and is causing a specific misfire code.
What is the OEM spark plug part number?
The Mazda OEM part number is typically PE5R-18-110. This corresponds to the NGK Laser Iridium plug, model ILKAR7L11.
Helpful Videos
Technical Specifications
OEM Part Numbers: PE5R-18-110 PE5S-18-110 0000-18-L3Y3
Material: Iridium Recommended OEM Brand: NGK NGK Part Number: ILKAR7L11 (or 94124) Socket Size: 14mm Factory Gap: ~0.044 inches
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Mazda 3 Sport: