When to replace spark plugs on Lexus RX 350?

Most Lexus RX 350 models with the 3.5L V6 use long-life spark plugs that are designed to last about 120,000 miles; however, the exact interval can vary by year and engine configuration. Always check your owner's manual or ask a dealer for your specific model and driving conditions.

How often to replace spark plugs on the RX 350

Below is a practical guide to replacement intervals for the RX 350, focusing on the common 3.5L V6 (2GR-FE) and typical OEM long-life plugs. It’s important to consult the owner’s manual for your exact year and configuration.

Plug types and lifespans

The RX 350's 3.5L V6 (2GR-FE) generally uses long-life iridium or platinum plugs. Replacements are typically scheduled around 120,000 miles (192,000 km). Some older variants may have used copper plugs, which wear faster and may require maintenance around 60,000–90,000 miles. Always confirm with the exact owner’s manual for your year and trim, because there have been updates across generations.

• 120,000 miles (192,000 km) for factory long-life iridium/platinum plugs common on most RX 350 models.


• 60,000–90,000 miles (96,000–145,000 km) if your vehicle uses copper or non-long-life plugs or if an aftermarket replacement was installed.


• In severe driving conditions—frequent short trips, heavy towing, extremely hot or cold climates—plan for earlier service and inspect around 60,000–90,000 miles.

In practice, the prevailing guideline for most RX 350 owners is around 120,000 miles, but your manual takes precedence and your driving style can shift maintenance windows.

Signs that spark plugs may need replacement

To avoid surprise failures, watch for symptoms that indicate worn or fouled plugs, which can affect starting, idle, and performance.

• Rough idle or engine misfires, especially at idle or during acceleration.


• Reduced power, sluggish acceleration, or hiccups when cruising.


• Lower fuel economy and higher emissions readings.


• Difficulty starting the vehicle or frequent cold-start issues.


• Check Engine Light with misfire-related codes (P0300 series) or running rough diagnostics.


• Visible wear, fouling, or deposits on accessible plugs during inspection.

Noticing any of these symptoms should prompt a diagnostic check. A technician can determine whether replacement is the right remedy or if other components (coils, sensors) are involved.

DIY vs professional spark plug replacement

Choosing between do-it-yourself or having a shop perform the replacement depends on your skill level and the RX 350’s model year.

• Labor time varies by year and access; expect around 1–2 hours at a shop, depending on repair facility and engine variant.


• Parts cost: OEM or high-quality aftermarket plugs typically range from about $8–$20 each, depending on plug type and brand.


• Important to use the correct plug type and torque specification as outlined in the service manual; some models specify not to use anti-seize compounds and to follow recommended gapping.


• On some RX 350s, ignition coil removal or access to rear bank spark plugs may require more disassembly; evaluate whether professional service is prudent.

For most drivers, a reputable shop or dealership offers a straightforward option with warranty. If you are comfortable with hands-on maintenance and have the right tools, refer to the owner’s manual and service guides for a step-by-step procedure and torque specs.

Summary

Across most Lexus RX 350 models, spark plug replacement is typically scheduled around 120,000 miles when OEM long-life plugs are installed. Always verify this interval in your exact owner’s manual, as year-to-year updates exist. Severe conditions or prior plug-type changes can shift the timing earlier. Monitor performance and signs of wear, and choose a replacement approach—DIY or professional—that matches your experience and vehicle configuration. Regular maintenance helps preserve performance and efficiency over the lifetime of the vehicle.

Do I really need to change my spark plugs at 100,000 miles?

Yes, replacing spark plugs at 100,000 miles is a common and often necessary maintenance task, as many modern vehicles have spark plugs rated to last that long. However, the exact interval depends on your vehicle's make, model, and the type of spark plug installed, so you should always check your owner's manual for the manufacturer's specific recommendation. 
This video explains when to change spark plugs and what happens if you don't: 1mHonest Mechanic ColoradoYouTube · Dec 24, 2023
Why it's important

• Engine performance: Spark plugs that are past their prime can cause rough idling, poor acceleration, and decreased fuel efficiency. 
• Preventing damage: Over time, worn-out plugs can put extra stress on other components, like ignition coils, and may seize in the engine block, making them harder to remove later. 
• Preventative maintenance: Replacing spark plugs is a form of preventative maintenance that can prevent more costly repairs down the line. 

This video explains why it's important to change spark plugs at 100k miles: 52sWhite One Auto, LLCYouTube · May 19, 2021
What to consider

• Owner's manual: Your vehicle's owner's manual is the most reliable source for the correct replacement interval and recommended plug type. 
• Spark plug type: The lifespan of spark plugs varies by material. Iridium plugs are often rated for 100,000 miles or more, while other types like copper or platinum have shorter lifespans. 
• Driving conditions: Severe driving conditions can shorten the life of spark plugs, so your interval may be shorter than recommended if you frequently tow, drive in extreme temperatures, or frequently start and stop. 

How much does it cost to replace spark plugs in a Lexus RX350?

The cost to replace the spark plugs in a Lexus RX 350 typically ranges from approximately $575 to over $1,600, depending on the model year and where the service is performed. While some sources estimate the cost between $575 and $800, higher estimates can reach $1,600 due to labor, especially since accessing the spark plugs can be challenging on these vehicles. 
Cost breakdown

• Average cost: Many estimate a price between $575 and $800 for the service. 
• Dealer/shop price: Prices at a dealer or shop can range from about $725 to over $1,630, with older models like the 2010 RX 350 often being on the higher end. 
• Part cost: The price for individual spark plugs is relatively low, around $10 each, but labor significantly increases the total cost. 
• Labor cost: The higher price is mainly due to the complex labor required to access the spark plugs, which involves removing several engine parts. 

Factors that affect cost

• Model year: Newer models may have slightly lower costs, while older ones can be more expensive. 
• Location: Prices vary depending on the shop or dealership and your geographic location. 
• Additional services: The total price can increase if other services are recommended at the same time. 

What year to stay away from Lexus RX 350?

Years to avoid for the Lexus RX 350 include 2007, 2008, 2010, 2016, and 2017 due to common problems like oil leaks, engine issues, brake failures, and faulty sensors. The 2010-2012 models are particularly prone to a ruptured oil cooler line that can cause engine failure, while the 2007-2009 models had issues with cracking dashboards and a faulty brake master cylinder. The 2016 and 2017 models saw recalls related to airbags and issues with rain sensors, notes CoPilot.
 
You can watch this video to learn about the history of the Lexus RX 350 and common problems in different generations: 1mThe Miles DrivenYouTube · Dec 22, 2024
Years to avoid and why

• 2007–2009: These models are known for cracking dashboards and a faulty brake master cylinder that can lead to brake failure. 
• 2010–2012: A common and severe problem with these years is the oil cooler line, which can rupture and lead to engine failure. 
• 2016–2017: The 2016 model year had airbag recalls and was the first year of a new generation, which can lead to early bugs. The 2017 model had issues with the rain sensor and wipers, in addition to having its own airbag recalls. 

What to look for instead

• 2011–2015: These models generally have fewer issues, with the 2013–2015 models in particular being noted as more reliable. 
• 2018–2022: Models from these years are considered more reliable, especially those with the redesigned exterior. 
• 2020–2022: These are considered among the most reliable years, with the 2020 model year being a good choice. 

This video discusses the best Lexus RX 350 years to buy: 59sThe Miles DrivenYouTube · Dec 18, 2024

How often should spark plugs be changed on a Lexus RX 350?

120,000 Miles – While this may seem like a bit of a gap, everything in between 50,000 miles and 120,000 miles is just repeated services. However, at this point, you'll want to have your spark plugs replaced. 150,000 Miles – At this service interval, you'll need a variety of repeated services completed.