why is my Toyota RAV4 XA40 (2013-2018) losing coolant but no visible leaks

Solution

1. Preparation

• Gather Tools: OBD-II scanner, cooling system pressure tester, compression tester, socket set, and safety gloves.
• Safety Precautions: Allow the engine to cool completely before working on the cooling system. Disconnect the battery.

2. Replace Head Gasket (if applicable)

• Sub-steps:
  1. Drain the engine coolant into a clean container.
  2. Remove the intake manifold and exhaust manifold (mark or label all connections).
  3. Unbolt the cylinder head and carefully lift it off.
  4. Clean the surfaces of the cylinder head and engine block to ensure a proper seal.
  5. Install a new head gasket, ensuring proper alignment with dowel pins.
  6. Reinstall the cylinder head and torque bolts to the manufacturer's specifications (typically 58 ft-lbs, refer to the service manual).
  7. Reassemble the intake and exhaust manifolds.

3. Replace Heater Core (if applicable)

• Sub-steps:
  1. Disconnect the battery and drain the coolant.
  2. Remove the dashboard or access panel to reach the heater core.
  3. Disconnect the heater core hoses from the engine bay and remove the core.
  4. Install the new heater core and reconnect hoses.
  5. Reassemble the dashboard or access panel.

4. Refill and Bleed Cooling System

• Sub-steps:
  1. Refill the cooling system with the appropriate type of coolant (Toyota Genuine Super Long Life Coolant).
  2. Start the engine and let it idle with the heater on high to bleed air from the system.
  3. Monitor the coolant level and top off as necessary.