2019 Toyota RAV4 Spark Plug Type & Gap

Quick reference

Engine	OEM Plug PN (Denso)	Aftermarket (NGK)	Gap (in/mm)	Torque (lb-ft / Nm)	Interval (miles / km)
2.5L I4 (A25A-FKS)	Denso FK16TT	NGK SILK4A10TT	0.039-0.043 in / 1.0-1.1 mm	13 lb-ft / 18 Nm	120,000 miles / 192,000 km
2.5L I4 Hybrid (A25A-FXS)	Denso FK16TT	NGK SILK4A10TT	0.039-0.043 in / 1.0-1.1 mm	13 lb-ft / 18 Nm	120,000 miles / 192,000 km

Why the right plug matters

Using the correct spark plug in your 2019 Toyota RAV4 is crucial for optimal engine performance, fuel efficiency, and longevity. The "right plug" refers to several key specifications: heat range, electrode material, and physical dimensions.

Heat range

Spark plugs are designed with a specific "heat range" which determines how quickly they dissipate heat from the combustion chamber. A plug that's too hot (dissipates heat slowly) can lead to pre-ignition and detonation, causing severe engine damage. A plug that's too cold (dissipates heat too quickly) can foul with carbon deposits, leading to misfires and poor performance. Toyota engineers carefully selected the Denso FK16TT (or equivalent NGK SILK4A10TT) with the ideal heat range for the RAV4's 2.5L engines.

Electrode metal

Modern spark plugs primarily use iridium or platinum for their electrodes, offering superior durability and extended service intervals compared to traditional copper plugs.

• Iridium: This is the most common material in your RAV4's OEM plugs. Iridium is extremely hard and has a very high melting point, allowing for very fine electrodes. This thin electrode concentrates the spark, improving ignition efficiency and extending the plug's lifespan significantly – often exceeding 100,000 miles.
• Platinum: Platinum is also durable and corrosion-resistant, but not as hard as iridium. Platinum plugs typically have slightly thicker electrodes than iridium and offer a good balance of performance and longevity, often lasting 60,000-100,000 miles. Double platinum plugs offer even greater lifespan by having platinum on both the center and ground electrodes.
• Copper: While excellent conductors, copper electrodes are soft and wear quickly. They are typically found in older vehicles or high-performance naturally aspirated engines where frequent replacement is acceptable. Your 2019 RAV4 is not designed for copper plugs.

The Denso FK16TT and NGK SILK4A10TT are iridium-tipped spark plugs, designed for long life and consistent performance.

How to gap a spark plug

While most iridium and platinum plugs come pre-gapped, it's always a good idea to verify the gap before installation, especially with a new set. However, do not attempt to adjust the gap on fine-wire iridium or platinum plugs unless absolutely necessary and with extreme care, as you can easily damage the delicate electrode.

For your 2019 RAV4, the specified gap is 0.039-0.043 inches (1.0-1.1 mm).

To check the gap:

1. Use a wire-style feeler gauge: These gauges are less likely to damage the delicate iridium tip than traditional ramp-style gauges.
2. Slide the correct-sized wire through the gap: It should slide through with light resistance. If it's too loose or too tight, the plug may need adjustment or replacement if damaged.
3. Adjusting (if absolutely necessary): If the gap is slightly off and you must adjust, use a spark plug gapping tool that bends the ground electrode ONLY. Be extremely gentle to avoid bending or damaging the fine iridium center electrode or the porcelain insulator. For iridium plugs, it's often safer to replace a plug with an incorrect gap than to attempt to adjust it.

Replacement procedure tips

The 2019 Toyota RAV4 uses a coil-on-plug (COP) ignition system, meaning each spark plug has its own dedicated ignition coil directly mounted on top of it. This eliminates the need for a distributor and spark plug wires, improving ignition efficiency and reliability.

1. Cool engine: Always perform spark plug replacement on a cool engine to prevent stripping threads in the aluminum cylinder head.
2. Disconnect battery: For safety, disconnect the negative battery terminal before starting work.
3. Remove engine cover: If equipped, remove any plastic engine covers to access the ignition coils.
4. Disconnect coil connectors: Carefully disconnect the electrical connectors from each ignition coil. They often have a release tab that needs to be pressed.
5. Remove coil retaining bolts: Each coil will have a small bolt (usually 10mm) holding it to the valve cover. Remove these bolts.
6. Remove ignition coils: Gently twist and pull the ignition coils to remove them from the spark plug wells. Be careful not to damage the rubber boots at the bottom of the coils.
7. Clean around plugs: Before removing the old plugs, use compressed air to blow out any dirt or debris from the spark plug wells. This prevents contaminants from falling into the combustion chamber when the old plugs are removed.
8. Remove old spark plugs: Use a spark plug socket with a rubber insert (to protect the porcelain and hold the plug) and a ratchet to carefully remove the old spark plugs. Turn counter-clockwise.
9. Anti-seize debate: For spark plugs going into aluminum cylinder heads, the use of anti-seize compound is a topic of debate. Most modern spark plugs (like your Denso/NGK iridium plugs) have a special coating on the threads, and manufacturers like NGK and Denso generally advise against using anti-seize. Applying it can alter the friction coefficient and lead to over-torquing, potentially damaging the cylinder head threads or the spark plug. Follow the plug manufacturer's recommendation. If you do use anti-seize, use a very small amount and reduce the torque specification by about 10-20%.
10. Install new plugs: Thread the new spark plugs in by hand first to avoid cross-threading. Once they are finger-tight, use a torque wrench to tighten them to the specified 13 lb-ft (18 Nm). Never over-tighten spark plugs.
11. Dielectric grease on boots: Apply a small amount of dielectric grease inside the rubber boots of the ignition coils. This helps seal out moisture, prevents corrosion, and makes future removal easier.
12. Reinstall coils and connectors: Reinstall the ignition coils, secure them with their bolts, and reconnect the electrical connectors. Ensure they "click" into place.
13. Reinstall engine cover and reconnect battery: Put back any engine covers and reconnect the negative battery terminal.

Known issues

Fortunately, the 2019 Toyota RAV4 with its A25A-FKS and A25A-FXS engines does not have widespread, notorious spark plug-related issues like the Ford 3-valve 2-piece spark plug breakage or GM's spark plug ionization-sensing coil problems. Toyota's 2.5L Dynamic Force engines generally have a solid reputation for reliability.

However, general spark plug issues can still occur if maintenance is neglected or incorrect parts are used:

• Misfires: Worn or fouled spark plugs can lead to misfires, causing rough idling, reduced power, and decreased fuel economy.
• Poor fuel economy: Inefficient ignition from worn plugs wastes fuel.
• Check Engine Light (CEL): Misfires or other ignition system issues will illuminate the CEL, typically with codes like P0301-P0304 (Cylinder 1-4 Misfire Detected).
• Cracked porcelain: Though rare with proper handling, impacts or excessive force during installation can crack the porcelain insulator, leading to misfires.

Always use the specified Denso FK16TT or NGK SILK4A10TT plugs to ensure your RAV4 runs its best.

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