2003–2009 Nissan 350Z
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 2003–2009 Nissan 350Z is rated Advanced and takes about 1–2 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 the gasoline/ICE engine in 2003-2009 Nissan 350Z; 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
Both are 60-degree V6s with six spark plugs and six coil-on-plug coils — three per bank, sitting on top of each valve cover. Park on level ground, set the parking brake, and let the engine cool fully before touching the aluminum heads.
Remove the plastic engine cover and the intake ducting as needed to expose both valve covers — on the VQ35DE this means the main cover over the intake plenum area, while the HR's cover has a different shape but comes off the same way.
I use anti-seize sparingly and only where specified. Modern plugs often don't need it. I replace plug wires as a set with plugs on older cars. They age together.
Press the release tab on each coil's electrical connector and unplug it, then remove the 10mm hold-down bolt from each coil — note that the coil bolt is longer than the surrounding 10mm bolts, so keep it with the coils.
Using a 16mm (5/8-inch) deep spark plug socket on an extension, loosen and remove each plug. Inspect each old plug: even, light-tan coloring across all six is ideal, while one oil-fouled plug points to a valve-cover seal issue on that bank.
Check the electrode gap of every new plug against the specification in the owner's manual or on the under-hood emissions sticker; do not assume the factory gap is correct. Never install a plug that has been dropped.
Thread each plug in by hand, turning the extension with your fingers until the washer contacts the cylinder head. The VQ35's aluminum heads cross-thread easily if a plug is started with a ratchet, so take your time feeling the threads engage. Once finger-tight, tighten roughly a quarter to a half turn further to crush the washer and seat the plug. Overtightening can strip the threads or crack the insulator — snug and seated is the goal.
Press each coil firmly onto its plug, reinstall the six 10mm hold-down bolts, and reconnect every electrical connector until it clicks. Refit the strut tower brace (if removed), intake ducting, and engine cover. Check for leftover tools. Start the engine and confirm a smooth idle with no warning lights. Take a spirited test drive — the VQ35 revs freely to redline, and any hesitation or misfire up top means a coil or plug is not fully seated.
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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2003–2009
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2003–2009
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