2020 Nissan Altima — Spark Plug Type, Gap & Torque

Quick reference

Engine	OEM Plug PN	Aftermarket (NGK/Denso/Motorcraft)	Gap (in/mm)	Torque (lb-ft / Nm)	Interval
2.5L I-4 (PR25DD, direct injection)	Nissan OEM (NGK Laser Iridium) — verify exact PN by VIN	NGK Laser Iridium; Denso Iridium (catalog cross-ref); Motorcraft cross-ref (catalog)	0.043 in (1.1 mm)	18 lb-ft (25 Nm)	Iridium: ~105,000 mi (168,000 km)
2.0L I-4 VC‑Turbo (KR20DDET)	Nissan OEM (NGK/Denso Iridium) — verify exact PN by VIN	NGK Iridium; Denso Iridium (catalog cross-ref); Motorcraft cross-ref (catalog)	0.028–0.031 in (0.7–0.8 mm)	18 lb-ft (25 Nm)	Iridium: ~60,000 mi (96,000 km)

Notes:

• Nissan supplies fine-wire iridium plugs from NGK (and in some applications Denso). Exact part numbers depend on engine, calibration, and production date. Always confirm by VIN in the Nissan EPC or the plug maker’s catalog. We do not list PNs here to avoid errors.
• Plugs are typically pre-gapped. Verify gap but avoid bending the iridium center electrode.

Why the right plug matters

Choosing the correct spark plug for your 2020 Altima ensures proper combustion, cold starts, fuel economy, and long coil life.

• Heat range: The PR25DD and KR20DDET have different combustion and thermal profiles. A plug that is too hot can cause pre-ignition/knock; too cold can foul. Use the exact heat range specified by Nissan/NGK/Denso for your engine code.
• Electrode metal:
  • Iridium: Factory equipment on both engines. Extremely durable fine-wire center electrode for strong spark at low coil energy and long life (60k–105k+ miles depending on engine).
  • Platinum: Acceptable in some cross-references but shorter life (~60k miles) and not typically OE on this platform.
  • Copper/nickel: Great conductivity but short service life (~20–30k miles). Not recommended for modern direct-injection/turbo systems.

How to gap a spark plug

Most iridium plugs arrive correctly set, but it’s smart to check.

• Use a wire-style feeler gauge, not a coin/wedge. Target: about 0.043 in (1.1 mm) for the 2.5L; 0.028–0.031 in (0.7–0.8 mm) for the VC‑Turbo. Confirm against the under-hood label or service data for your exact VIN.
• Check drag: The gauge should pass with light, even resistance.
• If adjustment is required, bend only the ground strap. Do not press on or pry against the fine iridium center electrode. Make very small changes and re-check.

Replacement procedure tips (2020 Altima)

Both engines use coil-on-plug (COP) ignition—no distributor.

1. Preparation

• Cold engine, clean work area. Remove the engine cover. Compressed air helps blow debris away from coil wells before unplugging.
• Disconnect the negative battery cable if desired (prevents accidental shorting while unplugging coils).

2. Coil removal

• Unplug each coil electrical connector and remove the small retaining bolt (typically 10 mm head). Gently twist and lift the coil to avoid tearing the boot.

3. Plug removal

• Use a 5/8" spark plug socket with a rubber insert or magnet. Break torque smoothly. If a plug resists, stop—add a drop of penetrating oil and allow time to wick into the threads.

4. Installation

• Inspect new plugs. Verify part number and gap. Do not drop them; a dropped plug can crack the porcelain.
• Anti-seize: Not recommended on modern NGK/Denso nickel-plated threads. If anti-seize is used against manufacturer guidance, reduce torque about 20% to avoid over-tightening.
• Thread in by hand until the gasket seats. Final tighten with a torque wrench to about 18 lb-ft (25 Nm) unless your service manual for the exact plug size specifies otherwise.
• Apply a small dab of dielectric grease inside each coil boot to help sealing and future removal. Reinstall coils and connectors; re-fit the engine cover.

5. Post-service

• Clear any stored misfire codes, start the engine, and verify smooth idle. A short test drive under light and moderate load helps confirm no misfires under boost (VC‑Turbo) or during tip-in.

Known issues

• No Ford-style 3‑valve two-piece plug breakage applies here; Nissan uses conventional one-piece plugs.
• Misfire under load on VC‑Turbo engines is often plug-condition sensitive. If mileage is high or fuel quality has been poor, new OE-spec iridium plugs usually restore performance.
• Coil boots can carbon-track if plugs are overdue. Inspect boots for white/light-gray lightning-like lines; replace affected coils/boots.
• Oil in plug wells from a valve cover gasket leak can cause misfires. Address the leak and clean the wells before installing new plugs.

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