A Guide to Replacing Spark Plugs on Your 2014-2018 Toyota Corolla
Keep your Corolla's 1.8L engine running smoothly with the right set of new aftermarket spark plugs.
- For best results, use Iridium spark plugs from OEM brands Denso or NGK.
- Replacement is a simple DIY job that takes about an hour with basic tools.
- Worn spark plugs cause rough idle, poor fuel economy, and hesitation; replace them to restore performance.
- Do not adjust the gap on new iridium plugs; the fine tip is fragile and can be easily damaged.
Signs of Failing Spark Plugs in Your Corolla
When your spark plugs start to wear out, your car will usually let you know. The signs can be subtle at first but will get worse over time. Ignoring them can lead to more expensive repairs, like damage to your catalytic converter.
- Rough Idling: Your car may shake or vibrate when you're stopped at a light.
- Poor Acceleration: The car feels sluggish or slow to respond when you press the gas pedal.
- Worse Fuel Economy: You might notice you're filling up your gas tank more often than you used to.
- Engine Misfires: The engine may sputter or hesitate, and you might feel a jerking sensation while driving.
- Trouble Starting: The engine takes longer to crank over or fails to start.
- Check Engine Light: A misfire caused by a bad spark plug will often trigger the check engine light.
Choosing the Right Aftermarket Spark Plugs
For your 2014-2018 Corolla, sticking with the original equipment (OEM) style is your best bet. Toyota used high-quality iridium spark plugs from the factory, supplied by either Denso or NGK. These two brands are highly recommended by mechanics and Corolla owners for their reliability and performance.
Pro Tip: Denso and NGK are the original equipment manufacturers for Toyota. Choosing their iridium aftermarket plugs is the closest you can get to factory quality and is a safe choice for performance and longevity.
Brand Quality Tiers
- Tier 1 (OEM-Equivalent): Denso and NGK. These brands manufactured the original plugs for your Corolla. They offer the best fit and performance. When buying, ensure they are from a reputable auto parts source, as counterfeit plugs are sometimes sold online.
- Tier 2 (Reputable Aftermarket): Bosch. Bosch makes quality iridium and platinum plugs that will work in a Corolla. However, many Toyota specialists and owners prefer to stick with Denso or NGK, as Bosch is often more associated with European vehicles.
- Tier 3 (Economy): Champion and other value brands offer basic platinum or copper plugs. While they are less expensive, they will not last as long as the factory-specified iridium plugs and may not provide the same level of performance. The 1.8L engine is designed for iridium plugs, so it's best to avoid downgrading.
Warning: The 2014-2018 Corolla requires iridium spark plugs. Do not use cheaper copper or standard platinum plugs, as they will wear out much faster and can negatively affect engine performance and fuel economy.
DIY Replacement: What to Expect
Replacing the spark plugs on this Corolla is a very DIY-friendly job that most owners can do at home. The four ignition coils and spark plugs are located right on top of the engine, under a plastic cover that pops off easily. The job requires only basic hand tools and about an hour of your time.
Cost to Replace Spark Plugs (2014-2018 Toyota Corolla)
| Option | Estimated Cost (4 Plugs) |
|---|---|
| New Aftermarket (DIY) | $32 - $113 |
| New OEM (DIY) | $52 - $80 |
| Professional Installation (Independent Shop) | $199 - $287 (Parts & Labor) |
| Professional Installation (Dealership) | $362 - $426 (Parts & Labor) |
Frequently Asked Questions
How often should I replace the spark plugs on a 2014-2018 Corolla?
The recommended replacement interval for the factory iridium spark plugs varies, with sources suggesting anywhere from every 60,000 to 120,000 miles. A safe and practical interval to follow for maintaining peak performance is to inspect them at 60,000 miles and plan for replacement by 100,000 miles.
What is the correct spark plug gap? Do I need to gap them?
The correct gap is approximately 0.043 - 0.044 inches. However, iridium spark plugs come pre-gapped from the factory. You should not attempt to adjust the gap yourself, as the fine iridium tip is very brittle and can easily break. You can verify the gap with a feeler gauge, but if it's incorrect, you should return the plug for a new one.
Is it okay to mix different brands of spark plugs?
No, you should always replace all four spark plugs at the same time with a matching set from the same brand. Using different plugs can cause inconsistent performance across the engine cylinders.
Do I need a special tool to replace the spark plugs?
You will need a 14mm thin-wall spark plug socket, which is slightly different from a standard socket. It has a rubber insert or magnet to hold the spark plug securely during removal and installation. A torque wrench is also highly recommended to tighten the new plugs to the correct specification (13 ft-lbs) and avoid damaging the engine's cylinder head.
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Technical Specifications
OEM Part Numbers: 90919-01247 90919-01253 SC20HR11 (Denso) ILKAR7B11 (NGK)
Material: Iridium, Quantity: 4, Required Socket: 14mm Thin Wall, Gap: 0.043 in (pre-gapped), Torque: 13 ft-lbs.
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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.
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