Replace the heater hoses that route coolant from the engine to the heater core and back, restoring proper cabin heating and preventing coolant leaks.

Warnings

Tools required

Parts

• Heater inlet hose × 1 — Use OEM specification
• Heater outlet hose × 1 — Use OEM specification
• Hose clamps (if reusing OEM spring clamps is not desired) × 4 — Use OEM specification
• Engine coolant × 1 — Toyota Super Long Life Coolant (Pink)

Fluids

• Toyota Super Long Life Coolant (Pink) — 2.5 qt

Preparation

1. Ensure the engine has been off for at least 2 hours and is completely cool to the touch
2. Park the vehicle on level ground and engage the parking brake
3. Place a drain pan under the radiator drain plug located at the bottom of the radiator
4. Remove the engine splash shield if equipped using 10mm bolts
5. Verify you have the correct replacement heater hoses for your specific RAV4 model year

Procedure

1. 1

   Drain the cooling system
   Slowly loosen the coolant reservoir cap to release any residual pressure. Open the radiator drain plug at the bottom of the radiator using a 10mm socket and drain approximately 2-3 quarts of coolant into the drain pan. This will lower the coolant level below the heater hoses to minimize spillage.
   Torque spec

   Coolant Drain Plug15 Nm (11 lb-ft)
2. 2

   Remove the engine cover
   Pull upward firmly on the engine cover to detach it from the mounting grommets. Set it aside in a clean area. This provides access to the top of the engine bay where the heater hoses connect.
3. 3

   Locate the heater hoses
   Identify the two heater hoses on the passenger side of the engine bay. The inlet hose connects from the engine coolant outlet to the firewall, and the return hose routes from the firewall back to the water pump or coolant pipe. Trace both hoses from the engine to the firewall connections.
4. 4

   Disconnect the inlet heater hose at the engine
   Using hose clamp pliers or a flathead screwdriver, release the hose clamp securing the inlet heater hose to the engine-side fitting. Slide the clamp away from the connection point. Twist the hose gently while pulling to break it free from the fitting. Be prepared for residual coolant to drain out.
5. 5

   Disconnect the inlet heater hose at the firewall
   Access the firewall connection point from inside the engine bay. Release the hose clamp and remove the inlet hose from the firewall nipple. You may need to reach behind other components or remove trim pieces for better access. Twist and pull the hose to remove it completely.
6. 6

   Disconnect the outlet heater hose at the engine
   Locate the return/outlet heater hose connection at the water pump or coolant pipe. Release the hose clamp and slide it back along the hose. Twist and pull the hose to separate it from the fitting. Allow any remaining coolant to drain into your drain pan.
7. 7

   Disconnect the outlet heater hose at the firewall
   Release the hose clamp at the firewall connection for the outlet hose. Remove the hose from the firewall nipple, twisting as needed to break any corrosion seal. Remove the complete outlet hose from the vehicle.
8. 8

   Clean the connection points
   Using shop towels, clean all coolant residue from the engine-side and firewall-side connection nipples. Inspect each fitting for cracks, corrosion, or damage. Replace any damaged fittings before installing new hoses.
9. 9

   Install the new inlet heater hose
   Route the new inlet heater hose from the engine coolant outlet to the firewall connection. Ensure the hose follows the same path as the original and does not contact any sharp edges or moving components. Slide new hose clamps onto the hose before making connections. Push the hose firmly onto the engine-side fitting until it bottoms out, then position the clamp 5-10mm from the end of the hose and tighten to specification. Repeat for the firewall connection.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
10. 10

    Install the new outlet heater hose
    Route the new outlet heater hose from the firewall to the water pump or coolant pipe connection. Slide new hose clamps onto the hose. Connect the firewall end first, pushing the hose fully onto the nipple and securing with a clamp positioned 5-10mm from the hose end, tightened to specification. Then connect and secure the engine end in the same manner.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)
11. 11

    Close the drain plug and refill coolant
    Close the radiator drain plug and torque to specification. Using a funnel, add Toyota Super Long Life Coolant (pink) to the coolant reservoir until it reaches the MAX line. Start with a 50/50 mixture of coolant and distilled water unless using pre-mixed coolant.
    Torque spec

    Coolant Drain Plug15 Nm (11 lb-ft)
12. 12

    Bleed air from the cooling system
    Start the engine and allow it to idle with the heater set to maximum temperature and fan on high. Watch the coolant level in the reservoir and add coolant as the level drops due to air purging from the system. Run the engine until the cooling fans cycle on and off at least once, indicating full operating temperature has been reached. Squeeze the upper radiator hose to help purge trapped air bubbles.
13. 13

    Check for leaks and top off coolant
    With the engine running, carefully inspect all four heater hose connections for any signs of coolant leakage. Tighten clamps if minor seepage is observed. Turn off the engine and allow it to cool for 15 minutes. Recheck the coolant level in the reservoir and top off to the MAX line if needed. Install the coolant reservoir cap securely.

Reassembly

1. Reinstall the engine cover by aligning the grommets and pressing down firmly until it clicks into place
2. Reinstall the engine splash shield if it was removed, torquing bolts to 27 Nm (20 lb-ft) if they are mounting bolts
3. Wipe down the engine bay to remove any coolant residue or spills

Verification

• Start the engine and verify the heater produces hot air when set to maximum temperature
• Check the coolant level in the reservoir after the engine has cooled - it should be at the MAX line
• Inspect all four heater hose connections for any signs of coolant leakage or seepage
• Verify the engine temperature gauge reads in the normal range and the cooling fans cycle properly
• Take a short test drive and recheck for leaks and proper heater operation afterward

More procedures for this vehicle