why does my Toyota Highlander Third Generation (2014-2019) lose coolant without a leak

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent any electrical issues.

2. Pressure Test the Cooling System

• Use a cooling system pressure tester to pressurize the system.
• Observe if the pressure drops over time, indicating a leak.
• If a leak is detected, identify the source (e.g., water pump, hoses, gaskets).

3. Inspect and Replace the Head Gasket (if necessary)

• Remove the intake manifold and cylinder head.
• Clean the mating surfaces thoroughly.
• Install a new head gasket, ensuring correct orientation and alignment.
• Reinstall the cylinder head with the specified torque sequence and torque values (follow manufacturer specifications).
• Reassemble the intake manifold and all associated components.

4. Replace Other Seals and Gaskets

• Inspect and replace any damaged gaskets or seals, especially the intake manifold gasket.
• Ensure all seals are properly lubricated during installation to prevent future leaks.

5. Refill Coolant and Bleed the System

• Refill the cooling system with the appropriate type of coolant (Toyota Genuine Super Long Life Coolant recommended).
• Bleed the cooling system to remove any trapped air.