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2021 Ford Explorer
2021 Explorer spark plug gaps and firing sequences for the 2.3L, 3.0L, 3.0L ST, 3.3L gasoline, and 3.3L hybrid.
Difficulty, time, and cost are estimates when this guide gives them. Torque is a cited figure, or it is left off.
Main source: 2021 Explorer Owner's Manual, first printing, August 2020, engine specifications (opens in a new tab), Ford Motor Company, published 2020-08-01, read 2026-10-15.
Numbers on this page come from the cited source. Match the engine before you use a capacity or a torque. Do not work under a vehicle held only by a jack.
Authorized dealer for spark plug replacement
Each parts footnote says to contact an authorized dealer for spark plug replacement.
| Item | Figure | Where it comes from |
|---|---|---|
| 2.3L EcoBoost | Motorcraft SP-578. Gap 0.028-0.031 in (0.7-0.8 mm). Firing order 1-3-4-2. Coil on plug. | 2.3L EcoBoost engine specifications and Motorcraft parts |
| 3.0L parts table and 3.0L specifications | Motorcraft SP-578 under the heading Motorcraft parts - 3.0L. Gap 0.028-0.031 in (0.7-0.8 mm). Firing order 1-4-2-5-3-6. | 3.0L engine specifications and Motorcraft parts |
| 3.0L ST specifications | Gap 0.028-0.031 in (0.7-0.8 mm). Firing order 1-4-2-5-3-6. The parts tables do not have a 3.0L ST heading, so no plug number is assigned to ST here. | 3.0L ST engine specifications |
| 3.3L gasoline and 3.3L HEV | Motorcraft SP-520 under the heading Motorcraft parts - 3.3L. Both specification pages print gap 0.049-0.053 in (1.25-1.35 mm) and firing order 1-4-2-5-3-6. | 3.3L gasoline and 3.3L HEV engine specifications and Motorcraft parts |
2.3L EcoBoost
3.0L
3.0L ST
3.3L gasoline
3.3L HEV
Firing sequence from the 2021 Explorer owner's manual engine specifications. Sequence only.
Illustration, not to scale; confirm with your owner's manual. This is the firing sequence only. It does not show where each cylinder sits on the engine.
Source for this drawing: 2021 Ford Explorer Owner's Manual, engine specifications, 2.3L EcoBoost, 3.0L, 3.0L ST, 3.3L gasoline, and 3.3L HEV.
2.3L, 3.0L, and 3.0L ST each print 0.028-0.031 in. Both 3.3L pages print 0.049-0.053 in.
2.3L EcoBoost is 1-3-4-2. The 3.0L, 3.0L ST, 3.3L gasoline, and 3.3L hybrid pages each print 1-4-2-5-3-6.
SP-578 is on the 2.3L and 3.0L parts tables. SP-520 is on the 3.3L parts table. The 3.0L ST page does not get a number from those headings.
Minimum fuel on each of these specification pages is 87 octane. The 3.0L ST horsepower note says 400 hp and 415 lb-ft when using premium fuel. That note is not a spark-plug instruction.
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Part
Motorcraft spark plug from the parts table for that heading
SP-578 on the 2.3L and 3.0L tables. SP-520 on the 3.3L table. No ST part number is printed.
Explorer Motorcraft parts (opens in a new tab)Search Amazon.com (affiliate link) (opens in a new tab)
Tool
Authorized dealer for spark plug replacement
Each parts footnote says to contact an authorized dealer for spark plug replacement.
2021 Explorer engine specifications (opens in a new tab)Search Amazon.com (affiliate link) (opens in a new tab)
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These guides cover the same kind of work. Their numbers belong to those vehicles, not to this one.