Replacing spark plugs in a 2009 Lexus ES 350 can be a challenging task, especially for the rear plugs. This guide will walk you through the process, providing tips and tricks to make the job easier.

Tools and Materials Needed

  • Metric socket set (10mm, 12mm, 14mm)
  • 5/8" spark plug socket
  • Ratchet and extensions
  • Torque wrench
  • New spark plugs (NGK or Denso recommended)
  • Anti-seize compound
  • Dielectric grease

Preparation

Before starting, ensure your engine is cool. Disconnect the negative battery terminal to prevent any electrical issues. Remove the engine cover by unscrewing the bolts at the front and lifting it off.

Accessing the Spark Plugs

Front Spark Plugs

  • Remove the plastic covers on either side of the engine bay
  • Disconnect the electrical connectors from the ignition coils
  • Remove the 10mm bolts securing the coils
  • Carefully pull out the ignition coils

Rear Spark Plugs

  • Remove the strut tower brace if present
  • Disconnect and carefully move aside any wiring harnesses obstructing access
  • Remove the metal bracket above cylinder 1 (two 12mm bolts)
  • Locate and disconnect the electrical connectors for the rear coils

Removing and Replacing Spark Plugs

  • Use the 5/8" spark plug socket to remove the old plugs
  • Check the new plugs' gap (should be 0.044 inches or 1.1mm)
  • Apply a small amount of anti-seize compound to the threads of the new plugs
  • Install the new plugs and torque to 13 ft-lbs (17 Nm)

Reinstalling Ignition Coils

  • Apply a small amount of dielectric grease to the inside of the coil boot
  • Carefully push the coils back onto the spark plugs
  • Secure with the 10mm bolts, torquing to 7 ft-lbs (9.5 Nm)
  • Reconnect all electrical connectors

Final Steps

  • Double-check all connections
  • Reinstall the engine cover and any removed components
  • Reconnect the battery

Tips for Success

  • Work on one cylinder at a time to avoid mix-ups
  • Use a magnetic spark plug socket to prevent dropping plugs
  • For rear plugs, a flexible extension or universal joint can be helpful
  • Take your time, especially with the rear plugs – patience is key

FAQs About Lexus ES 350 Spark Plug Replacement

    • How often should I change spark plugs in my Lexus ES 350?
      Typically every 60,000 to 120,000 miles, but consult your owner's manual for specific recommendations.
    • Can I replace just some of the spark plugs?
      It's best to replace all six spark plugs at the same time for optimal engine performance.
    • Do I need to replace the ignition coils when changing spark plugs?
      Not necessarily, but inspect them for damage or oil contamination. If in doubt, replacing them can prevent future issues.

Remember, if you're not comfortable with this task, it's always best to consult a professional mechanic. Improper installation can lead to engine performance issues or damage.