This procedure covers the removal and replacement of the heater control valve on a 2015-2020 Ford F-150 with the 5.0L Coyote V8 engine, including coolant drainage and system refill.

Warnings

Tools required

Parts

• Heater control valve × 1 — YW4Z-18495-AA or equivalent
• Hose clamps × 2 — Use OEM specification
• Coolant (if needed for top-off) × 1 — Motorcraft Orange Coolant

Fluids

• Motorcraft Orange Coolant — 2 qt

Preparation

1. Ensure engine is completely cold to the touch before beginning work
2. Park vehicle on level ground and apply parking brake
3. Place drain pan under radiator drain petcock location
4. Remove engine cover by pulling upward on the four corner grommets

Procedure

1. 1

   Drain coolant from system
   Locate the radiator drain petcock on the driver side lower corner of the radiator. Open the petcock by turning counterclockwise and drain approximately 2 gallons of coolant into the drain pan. This reduces coolant loss when removing the heater control valve. Close the petcock and tighten to specification.
   Torque spec

   Drain Petcock8 Nm (6 lb-ft)
2. 2

   Locate heater control valve
   The heater control valve is mounted on the passenger side firewall area, inline with the heater inlet hose. It is a small cylindrical valve with an electrical connector and two coolant hoses attached. Identify the valve and trace the hoses to understand the routing.
3. 3

   Disconnect electrical connector
   Press the locking tab on the heater control valve electrical connector and pull the connector straight off the valve. Move the wiring harness aside to provide working clearance.
4. 4

   Remove inlet hose clamp
   Using hose clamp pliers or a flat blade screwdriver, loosen or remove the hose clamp securing the inlet hose to the heater control valve. Slide the clamp back on the hose away from the valve connection point. Have shop towels ready to catch residual coolant.
5. 5

   Remove outlet hose clamp
   Similarly, loosen or remove the hose clamp on the outlet side of the heater control valve. Slide the clamp back along the hose. Expect some coolant spillage from both hoses.
6. 6

   Remove heater control valve mounting
   Remove the mounting bolt or bracket securing the heater control valve to the firewall or engine bay structure using an 8mm or 10mm socket. Once the mounting is loose, carefully twist and pull the hoses off the valve ports. Allow any remaining coolant to drain into the drain pan or shop towels.
   Torque spec

   Valve Mounting8 Nm (6 lb-ft)
7. 7

   Remove old heater control valve
   Remove the old heater control valve from the vehicle. Inspect the hose ends for damage, cracks, or hardening. Replace hoses if they show signs of deterioration.
8. 8

   Install new heater control valve
   Position the new heater control valve in the mounting location. Ensure the inlet and outlet ports are correctly oriented to match the hose routing. Install the mounting bolt and tighten to specification.
   Torque spec

   Valve Mounting8 Nm (6 lb-ft)
9. 9

   Reconnect coolant hoses
   Push both coolant hoses firmly onto the inlet and outlet ports of the new heater control valve. Ensure each hose is fully seated on the port barb. Install new hose clamps if the old ones are corroded or damaged. Position clamps over the hose-to-valve connection area and tighten to specification.
   Torque spec

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

    Reconnect electrical connector
    Push the electrical connector onto the heater control valve until it clicks into place. Verify the locking tab is fully engaged.
11. 11

    Refill cooling system
    Using the coolant funnel adapter attached to the radiator cap opening or degas bottle, slowly refill the cooling system with Motorcraft Orange Coolant to the proper level. Add coolant until it reaches the COLD FILL line on the degas bottle. Do not overfill.
12. 12

    Bleed air from cooling system
    With the degas bottle cap off, start the engine and allow it to warm up to operating temperature with the heater on maximum heat setting. Monitor coolant level and add as needed while the system purges air. Squeeze the upper radiator hose several times to help release trapped air. Once the thermostat opens and coolant circulates fully, top off the degas bottle to the HOT FILL line.
    ⚠Keep hands and tools away from moving cooling fans. Monitor coolant temperature to prevent overheating during bleeding process.
13. 13

    Final inspection and reinstallation
    Turn off the engine and allow it to cool for 15 minutes. Check coolant level and top off if necessary. Inspect all connections for leaks. Wipe down any coolant residue. Reinstall the engine cover by pressing the grommets into the mounting points.

Reassembly

1. Ensure all hose clamps are properly tightened and positioned over hose-to-valve connections
2. Verify electrical connector is fully locked onto heater control valve
3. Confirm coolant level is at HOT FILL line on degas bottle after engine reaches operating temperature
4. Check for coolant leaks around heater control valve connections after test drive

Verification

• Start the engine and set heater controls to maximum heat. Verify hot air blows from vents within 5-10 minutes of engine warm-up
• Check for coolant leaks at the heater control valve inlet and outlet connections with engine at operating temperature
• Verify no warning lights on instrument cluster related to engine temperature or coolant level
• Monitor coolant level in degas bottle for 24-48 hours after repair to ensure system remains properly filled
• Test heater control valve operation by cycling temperature controls from cold to hot and verifying smooth temperature transitions

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