2020 Ford F‑250 Super Duty — Spark Plug Type, Gap & Torque

Quick reference

Note: Ford publishes exact part numbers, torque, and gap by calibration. Never rely solely on a generic chart—confirm on the under‑hood emissions label and the official Motorcraft/Ford catalog using your VIN. We never list plug part numbers we can’t verify.

Why the right plug matters

Using the correct plug keeps combustion stable under heavy loads and towing—exactly what an F‑250 is built for. Key factors:

• Heat range: Too hot a plug can cause pre‑ignition; too cold can foul. Ford’s specified heat range is calibrated to each engine and model year. Stick with the OE heat range or the exact cross‑reference.
• Electrode material:
  • Iridium: Best longevity and stable spark, especially under high cylinder pressures. Typical OE on late‑model Ford gas V8s; service interval often around 100,000 miles.
  • Platinum: Mid‑grade life and cost; common aftermarket option. Around 60,000‑mile intervals.
  • Copper/nickel: Great conductivity but short life; usually 25,000–30,000 miles. Not ideal for long‑interval Super Duty service.
• Resistor design and shell dimensions: Thread reach, seat style (taper vs. gasket), and projected tip must match exactly. Do not substitute based on thread size alone.

How to gap a spark plug

Most OE iridium plugs come pre‑gapped close to spec, but always verify.

1. Check spec: Read the under‑hood emissions label or Ford service info for the exact gap.
2. Measure: Use a wire‑style gap gauge (preferred over coin/fan gauges for fine‑wire iridium). Slide the correct wire through the gap; it should drag lightly.
3. Adjust: If needed, place the ground strap on the tool’s notch and apply a light, even bend to the strap only. Never pry against or touch the fine‑wire center electrode.
4. Re‑check: Measure again in multiple spots. Consistency matters.

Replacement procedure tips (2020 F‑250 gas engines)

Both the 6.2L SOHC and 7.3L OHV are coil‑on‑plug (COP) systems. Work on a cold engine.

• Access and prep:
  • Disconnect the negative battery cable if you’ll be moving harness connectors extensively.
  • Blow debris out of the plug wells with compressed air before removing coils.
  • Label coil connectors if needed; each cylinder has its own coil.
• Coil removal:
  • Unplug the electrical connector and remove the coil hold‑down bolt.
  • Twist the coil boot gently to break the seal, then pull straight up. Inspect for oil or coolant intrusion; contamination causes misfires.
• Plug removal:
  • Use a quality, thin‑wall spark plug socket with extension. Crack each plug loose, then back out by hand to avoid cross‑threading.
  • If resistance is high, snug slightly and work the plug out in small increments. Do not force a dry, seized plug in an aluminum head.
• Installation:
  • Thread each new plug in by hand several turns. If it won’t spin freely, stop and correct the thread path.
  • Torque to Ford spec. As a general guide for taper‑seat, 14 mm plugs in aluminum heads run about 13–15 lb‑ft (18–20 Nm), but always confirm your engine’s exact value.
  • Anti‑seize: Ford/Motorcraft plated shells are designed to be installed dry. Adding anti‑seize changes friction and can lead to over‑torque and thread damage. Unless Ford specifies otherwise, install dry.
  • Dielectric grease: A small amount inside the coil boot helps sealing and future removal. Do not coat the terminal itself—just the inner boot.
  • Reinstall coils, torque the hold‑down bolts, reconnect connectors, clear any DTCs, and verify smooth idle.

Known issues and notes

• 3‑valve two‑piece plug breakage: Not applicable here. That concern affected older 5.4L/4.6L 3‑valve modular engines, not the 2020 6.2L or 7.3L.
• Broken shells/porcelain: Generally rare on these engines when removed cold and torqued correctly. Most breakage traces back to over‑torque or installing anti‑seize on plated shells.
• Water or dust in plug wells: Super Duty trucks see harsh service. After deep washes or off‑road use, moisture or debris can collect around COP boots, leading to misfires. Periodically inspect boots and seals.
• Diesel note: The 6.7L Power Stroke uses glow plugs, not spark plugs—different maintenance entirely.

Pro tip: Use the Motorcraft online catalog (or an NGK/Denso/ACDelco catalog) with your VIN to lock in the exact OE part number and any supersessions. Always set gap and torque to the values on your under‑hood label or Ford service information.

Need plugs replaced? Find a shop on Repairius.