2017–2021 Acura MDX
By Tom Becker ✓ Certified Mechanic · Published Sep 21, 2026 · Updated Oct 22, 2026
Save $335 by doing it yourself! Shop cost: $450
Quick answer: Spark Plug Replacement on a 2017–2021 Acura MDX is rated Advanced and takes about 1–1.5 hours. You'll need 6 tools for this job, and parts cost about $115. This guide walks you through the full job step by step, including the mistakes to avoid.
| Part Name | Part Number | Price | Buy |
|---|---|---|---|
| Correct spark plug set for 2017-2021 Acura MDX; verify engine, heat range, gap, and VIN fitment | — | $115.00 | |
| Coil-boot seals or ignition coils only if inspection finds damage Optional | — | $35.00 |
About prices: shown prices are typical retail averages and change frequently; cheaper alternatives may be available. Confirm the current price before buying.
💡 Pro tip: Order all parts at once to save on shipping
Follow these steps carefully
Most 2017–2021 MDXs carry the 3.5L V6 (J35Y5); the Sport Hybrid pairs a 3.0L V6 (J30Y1) with electric motors. Both are transverse V6s with six coil-on-plug coils, and the procedure is the same either way. Let the engine cool fully.
Loosen the negative battery cable clamp with a 10mm wrench, lift the cable off the post, and tuck it aside so it cannot spring back onto the terminal. You will lose radio presets and the clock, and the transmission may shift differently during a short relearn drive afterward.
I tuck the loose cable behind the battery hold-down — if it springs back onto the post while your hands are down in the plug wells, you'll know about it.
Lift off the plastic engine cover. The front bank's three coils are right in front of you: press each connector's release tab and slide it off, remove the 10mm coil bolt, twist the coil gently to break the boot loose, and lift it straight out.
Work a 5/8-inch spark plug socket with long extensions and a swivel joint into the gap between the plenum and the firewall, by feel. Press each coil's release tab by fingertip, unbolt the coil, and snake it out.
Loosen each plug counterclockwise with the socket-and-swivel setup, front bank first, then rear. Lift each old plug out with the socket's grip or a magnet. The rear-bank plugs typically look the worst since that bank runs hotter — compare all six.
Oil on the rear plug threads is the thing I watch for — it usually means the valve cover gasket is weeping. Note it now, because that gasket is tomorrow's job and you'll already know the bank.
Check every new plug with a feeler gauge against the owner's manual or the under-hood emissions sticker. The MDX runs long-life iridium plugs, and the fine-wire center electrode is fragile — adjust only the ground strap.
Thread each plug in BY HAND until the washer seats, turning the extension with your fingertips so you feel resistance early. Once seated, give roughly a quarter to half turn more with the ratchet.
Push each coil firmly back onto its plug, reinstall the 10mm bolts snugly, and reconnect every connector until it clicks — a half-seated rear-bank connector is the classic cause of a flashing check-engine light after this job. Press the engine cover back on.
A flashing check-engine light after this job is almost always one rear coil connector not clicked home. I tug-test every connector before the cover goes back on — blind connectors lie to your fingers.
Test your repair before closing everything up. If something doesn't work right, double-check your steps.
⚠️ Common Mistakes to Avoid
2017–2021
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2017–2021
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