why does my Toyota Highlander Third Generation (2014-2019) emit smoke from the exhaust?

Toyota Highlander Third Generation (2014-2019)

Error Codes

4-8 hours

Time

hard

Difficulty

high

Severity

3 min read

549 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and fix engine smoke issues in Toyota Highlander (2014-2019). Step-by-step guide with diagnostic procedures and repair instructions.

Affected Component

Engine

Estimated Time

4-8 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect battery before working on electrical systems.
•Allow engine to cool before opening any components.

Symptoms

•Blue or gray smoke visible from the exhaust
•Increased oil consumption
•Unusual engine noises (knocking or ticking)
•Check engine light illuminated
•Rough idle or engine stalling
•Strong smell of burnt oil

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify any engine faults.
2
Inspect the oil level and condition to check for signs of contamination or excessive consumption.
3
Check the coolant level and inspect for signs of oil in the coolant, indicating a possible head gasket failure.
4
Conduct a visual inspection of the exhaust system for any leaks or damage.
5
Perform a compression test to evaluate the engine’s internal condition.
6
Inspect the PCV (Positive Crankcase Ventilation) system for blockages or malfunctions.

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
•Socket set
•Torque wrench
•Compression tester
•Engine hoist

Parts Required

•Valve seals
•Piston rings (if necessary)
•Head gasket
•PCV valve

Related Faults

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify any engine faults.
2
Inspect the oil level and condition to check for signs of contamination or excessive consumption.
3
Check the coolant level and inspect for signs of oil in the coolant, indicating a possible head gasket failure.
4
Conduct a visual inspection of the exhaust system for any leaks or damage.
5
Perform a compression test to evaluate the engine’s internal condition.
6
Inspect the PCV (Positive Crankcase Ventilation) system for blockages or malfunctions.

Solution

1. Preparation

Gather necessary tools and parts.
Disconnect the battery to ensure safety while working on electrical components.
Allow the engine to cool if it has been running.

2. Addressing Oil Consumption

Replace Valve Seals:
- Remove the valve cover using a socket set.
- Replace old valve seals with new ones, ensuring proper seating.
- Reinstall the valve cover and torque to manufacturer specifications (typically around 7-10 Nm).
Replace Piston Rings (if necessary):
- Remove the engine from the vehicle for easier access.
- Disassemble the engine block to access the pistons.
- Replace worn piston rings with new ones, ensuring proper orientation and installation.
- Reassemble the engine and torque all components to manufacturer specifications.

3. Addressing Head Gasket Failure

Replace Head Gasket:
- Remove the intake and exhaust manifolds.
- Unbolt and remove the cylinder head.
- Clean the surfaces thoroughly to remove old gasket material.
- Install a new head gasket and reassemble the cylinder head with proper torque (typically around 25-30 Nm in a specific sequence).
- Reinstall manifolds and reconnect all components.

4. Inspecting and Replacing PCV Valve

Inspect PCV Valve:
- Locate the PCV valve in the engine compartment.
- Remove the valve and check for clogs or damage.
Replace if necessary:
- Install a new PCV valve, ensuring it fits securely.