Quick answer: Spark Plug Replacement on a 2016–2022 Lexus RX is rated Advanced and takes about 3–5 hours (rear bank requires intake plenum removal). You'll need 10 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 2016-2022 Lexus RX; verify engine, heat range, gap, and VIN fitment |
— |
$115.00 |
|
| Coil-boot seals or ignition coils only if inspection finds damage Optional |
— |
$35.00 |
|
| New surge-tank-to-manifold and throttle-body gaskets |
— |
— |
|
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
Step-by-Step Instructions
Follow these steps carefully
1
Know your V6: front bank easy, rear bank buried
The RX 350 in this range uses the 3.5L 2GR-FKS V6 with both port and direct injection — six iridium plugs, and Lexus calls for them around every 60,000 miles. The catch is layout: the front bank is easy, but the rear bank hides under the intake surge tank (plenum), which has to come off. The RX 450h hybrid uses the closely related 2GR-FXS Atkinson-cycle V6 with the same six-plug, plenum-off rear-bank job. Park flat, set the brake, let the engine cool fully, and disconnect the negative battery terminal.
2
Strip the beauty cover and do the front bank first
Remove the plastic beauty cover over the front bank — it is held by a few 5mm Allen bolts at the front edge and a threaded center emblem you turn counterclockwise. With the cover off, the three front coils are staring at you.
3
Swap the three accessible front plugs
With a 5/8-inch spark plug socket and a 6-inch extension, remove the three front plugs by hand once broken loose, and install the three new ones: check the gap with a feeler gauge against your owner's manual or the under-hood emissions sticker, hand-thread each plug into the aluminum head, then tighten to washer-seat plus roughly a quarter to a half turn. Reinstall the front coils with their bolts snug and connectors clicked. The front bank is now done — leave its cover off until the end.
4
Lift the intake plenum to expose the rear bank
Now the real work: the intake plenum. Disconnect the air intake duct, the throttle body connector and coolant hoses, the PCV and EVAP vacuum hoses, and any wiring clipped to the plenum — label every hose and connector with tape as you go. Unbolt the plenum (the bolts run around its perimeter) and lift it straight up. Immediately stuff clean rags into the six exposed intake runners. Have new surge-tank-to-manifold and throttle-body gaskets on hand; the old ones are not reusable.
5
Reach the rear bank against the firewall
With the plenum off, the three rear coils are finally accessible against the firewall. Disconnect each coil connector carefully (heat-aged tabs crumble; press, do not pry), remove the 10mm coil bolts, and pull the coils.
🔧 Mechanic's note — Tom Becker
I've seen this exact mistake come through the shop: Disconnect each coil connector carefully (heat-aged tabs crumble; press, do not pry), remove the 10mm coil bolts, and pull the coils.
6
Read the old plugs and double-check the new ones
Confirm every new plug's gap with a feeler gauge per the manual or emissions sticker; do not assume the box is right. Many modern iridium plugs are pre-coated at the factory, so follow the plug manufacturer's guidance on anti-seize rather than applying it by habit.
🔧 Mechanic's note — Ray Delgado
I know small thing, big difference: Many modern iridium plugs are pre-coated at the factory, so follow the plug manufacturer's guidance on anti-seize rather than applying it by habit.
7
Reseal the plenum
Pull the rags from the intake runners — count them, all six. Set the plenum down on its new gaskets, tighten the perimeter bolts evenly in a crisscross pattern until snug, and reconnect every hose, sensor, and the throttle body exactly as labeled.
All Done!
Test your repair before closing everything up. If something doesn't work right, double-check your steps.
⚠️ Common Mistakes to Avoid
- • Reusing the old intake plenum gaskets — they compress and harden; new surge-tank and throttle-body gaskets are cheap insurance against vacuum leaks.
- • Forcing a brittle coil connector tab until it snaps — support the connector body while you press the tab.
- • Dropping a bolt or rag into an open intake runner — stuff clean rags in the runners the moment the plenum lifts.
