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What should I do if my 2021 Highlander is experiencing excessive exhaust smoke? - Toyota Highlander
Home/Cars/Toyota/Highlander/Fourth Generation (2020-present)/What should I do if my 2021 Highlander is experiencing excessive exhaust smoke?

What should I do if my 2021 Highlander is experiencing excessive exhaust smoke?

Toyota Highlander Fourth Generation (2020-present)

Error Codes
varies
Time
hard
Difficulty
medium
Severity
Navigation
ProblemSymptomsDiagnosisSolution
ProblemSymptomsDiagnosisSolution
4 min read
629 words

Problem Statement

Learn how to diagnose and repair excessive exhaust smoke issues in your 2021 Toyota Highlander with detailed steps and required tools.

Affected Component
engine
Estimated Time
varies

Symptoms

  • •Excessive Exhaust Smoke
  • •Poor Engine Performance
  • •Unusual Odors
  • •Fluid Leaks

Diagnostic Steps

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

  • ✓Test the affected component to ensure it functions correctly
  • ✓Check for any error codes or warning lights
  • ✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

  • •Follow the manufacturer's recommended maintenance schedule
  • •Address warning signs early before they develop into major issues
  • •Use quality parts and fluids recommended for your vehicle
  • •Keep detailed records of all repairs and maintenance

Tools & Equipment Required

  • •OBD-II Scanner
  • •Compression Tester
  • •Leak-Down Tester
  • •Socket Set
  • •Torque Wrench
  • •Screwdrivers
  • •Oil Catch Pan
  • •Clean Rags
  • •Safety Glasses and Gloves

Additional Information

Affected Component
engine
Estimated Time
varies
Difficulty
hard
Severity
medium
Tools Required
9 items

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Back to Generation

If your 2021 Toyota Highlander is experiencing excessive exhaust smoke, it is important to diagnose the problem accurately to prevent further damage to the engine. Below are detailed steps to identify the issue, along with the necessary tools and repair instructions.

Tools Required
  • OBD-II Scanner
  • Compression Tester
  • Leak-Down Tester
  • Socket Set
  • Torque Wrench
  • Screwdrivers
  • Oil Catch Pan
  • Clean Rags
  • Safety Glasses and Gloves
Repair Instructions

If Blue Smoke is Present (Burning Oil)

  1. Replace Valve Seals:

    • Remove the valve cover (ensure you replace the gasket).
    • Use a valve spring compressor to remove the springs and replace the seals.
    • Reassemble and torque the valve cover to specification.

  2. Replace Piston Rings (if necessary):

    • This requires significant disassembly:
      • Remove the engine from the vehicle.
      • Disassemble the engine to access the pistons.
      • Remove the oil pan and cylinder head.
      • Replace the piston rings.
      • Reassemble the engine and reinstall.

If White Smoke is Present (Coolant Leak)

  1. Check for a Blown Head Gasket:

    • Perform a chemical test for combustion gases in the coolant.
    • If the head gasket is blown:
      • Remove the cylinder head and replace the gasket.
      • Check for warping on the head, and resurface if necessary.
      • Reassemble, ensuring proper torque specifications.

  2. Inspect and Replace Cracked Engine Block (if needed):

    • If the block is cracked, it may require replacement or extensive repair.

If Black Smoke is Present (Too Much Fuel)

  1. Inspect Fuel Injectors:

    • Remove and test each injector for proper operation using a multimeter or injector tester.
    • Replace any faulty injectors.

  2. Check Fuel Pressure Regulator:

    • Test the regulator for proper pressure output.
    • Replace if defective.

  3. Inspect Mass Airflow Sensor (MAF):

    • Clean or replace the MAF sensor if it is dirty or malfunctioning.
Final Steps
  1. Clear Codes: After repairs, clear any trouble codes using the OBD-II scanner.
  2. Test Drive: Take the vehicle for a test drive to monitor for smoke and check engine performance.
  3. Monitor Oil and Coolant Levels: Ensure they are at appropriate levels after repairs.

If the smoke persists after these diagnostics and repairs, it may be advisable to consult a professional technician for further evaluation.