why is my Toyota RAV4 XA50 (2019-2024) losing coolant with no leaks visible

Solution

1. Preparation

• Tools Required: OBD-II scanner, cooling system pressure tester, compression tester, basic hand tools, torque wrench.
• Safety Warnings: Allow the engine to cool completely before starting work to avoid burns.

2. Head Gasket Replacement

1. Disconnect Battery: Remove negative battery terminal to prevent electrical shorts.
2. Drain Coolant: Place a drain pan underneath the radiator. Open the drain plug and let the coolant empty completely.
3. Remove Engine Components:
   • Remove the intake manifold, throttle body, and any components obstructing access to the cylinder head.
   • Label and store bolts and connectors for reassembly.
4. Remove Cylinder Head:
   • Unbolt the cylinder head using a torque wrench, following the manufacturer’s specified sequence.
   • Carefully lift the cylinder head off and inspect for warping or cracks.
5. Clean Surfaces: Use a scraper to clean the cylinder head and block surfaces of any old gasket material.
6. Install New Head Gasket: Place a new head gasket onto the engine block, ensuring it is aligned properly.
7. Reinstall Cylinder Head:
   • Position the cylinder head back onto the block.
   • Torque the head bolts to the manufacturer's specifications in the correct sequence.
8. Reassemble Components: Reinstall the intake manifold and any other components removed earlier.
9. Refill Coolant: Fill the cooling system with the appropriate type of coolant.

3. Additional Checks

1. Inspect Water Pump: Check the water pump for proper operation and leaks.
2. Thermostat Check: Consider replacing the thermostat if it is not functioning correctly.