my Toyota RAV4 heater is blowing cold air what could be wrong

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the engine is cool before starting work.
• Disconnect the battery for safety.

2. Check and Top Off Coolant

• Locate the radiator cap and carefully remove it.
• Inspect coolant levels in both the radiator and overflow tank, adding the appropriate coolant mixture if needed.
• Replace the radiator cap securely.

3. Replace Thermostat (if faulty)

• Drain the engine coolant into a suitable container.
• Disconnect the negative battery terminal and remove any components obstructing access to the thermostat housing.
• Remove the thermostat housing bolts using a socket set.
• Replace the thermostat with a new one, ensuring it is oriented correctly.
• Reattach the thermostat housing and torque bolts to factory specifications (usually around 15-20 lb-ft).
• Refill the cooling system with the appropriate coolant mixture and bleed any air from the system.

4. Inspect and Replace Heater Control Valve (if necessary)

• Locate the heater control valve; it is usually near the firewall.
• Disconnect the hoses attached to the valve, being careful to catch any spilled coolant.
• Remove the valve from its mounting using appropriate tools.
• Install the new heater control valve in the same orientation, tightening bolts to specifications.
• Reconnect the hoses securely.

5. Replace Cabin Air Filter

• Locate the cabin air filter compartment, usually behind the glove box.
• Open the glove box and remove any stops or clips holding it in place.
• Slide out the old cabin air filter, noting the orientation.
• Insert the new filter in the same orientation and reassemble the glove box.