2005–2012 Acura RL
By Tom Becker ✓ Certified Mechanic · Published Sep 21, 2026 · Updated Nov 7, 2026
Save $335 by doing it yourself! Shop cost: $450
Quick answer: Spark Plug Replacement on a 2005–2012 Acura RL is rated Advanced and takes about 1 to 1.5 hours — the front bank is quick, the firewall-side bank takes the time. 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 the gasoline/ICE engine in 2005-2012 Acura RL; 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
Park on level ground, set the parking brake, and let the engine cool completely. Disconnect the negative battery cable with a wrench and tuck it aside so it cannot touch the terminal.
Honda's J-series layout keeps them reachable without removing the manifold, but hand room back there is tight and you will be working partly by feel, so plan a 6-inch extension and a swivel for the rear three before you start.
I inspect the old plugs as they come out. They tell you about engine health — oil, fuel, and timing all leave clues.
Do one bank at a time and keep the coils in order on a clean rag — although the connectors are keyed, keeping the order eliminates any doubt on reassembly. Squeeze the release tab on each coil's electrical connector and pull it free; the plastic latches get brittle with age and heat, so squeeze deliberately rather than forcing them. Remove each coil's single retaining bolt and lift the coil straight out of the plug well with a gentle twist. Inspect each boot for cracks or white carbon tracking as it comes out — a failed boot causes misfires that new plugs alone will not fix.
Break each plug loose counterclockwise and spin it out. Note each old plug's condition in order — a single oil-fouled plug on one bank points at a valve-cover gasket leak worth fixing.
Read the electrode gap specification in your owner's manual or on the emissions sticker under the hood — the 3.5L and 3.7L can call for different plugs, so never use a generic gap value. Check each new plug with a wire-type or feeler gauge and adjust gently; never force the gauge against a fine-wire iridium electrode. Thread each new plug into the head by hand for several full turns until finger-tight. For the rear bank, lower the plug in on the socket and extension but start the threads with your fingertips on the extension — if it binds, back it out and restart instead of forcing it.
Tighten each plug with the socket until seated. Do not overtighten the aluminum heads. Lower each coil back onto its plug, reinstall the retaining bolt, and push the electrical connector on until the locking tab clicks — give each one a tug to confirm it is latched.
Reconnect the negative battery cable. Start the engine and let it idle — it should be smooth with no check-engine light. Take a short test drive with the radio off and listen for smooth power delivery, then confirm no misfire codes have returned.
Test your repair before closing everything up. If something doesn't work right, double-check your steps.
⚠️ Common Mistakes to Avoid
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