Heater Hoses

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

Warnings

Tools required

Parts

• Heater inlet hose × 1 — Use OEM specification
• Heater outlet hose × 1 — Use OEM specification
• Hose clamps (constant tension type) × 4 — Use OEM specification
• Motorcraft Orange Coolant concentrate × 1 — VC-3DIL-B

Fluids

• Motorcraft Orange Coolant — 3 qt

Preparation

1. Ensure engine is completely cold (wait at least 2 hours after last operation)
2. Park vehicle on level ground and engage parking brake
3. Place drain pan beneath radiator drain petcock location
4. Remove engine cover by pulling upward on front edge, then lifting off
5. Locate heater hoses at rear of engine on passenger side - one connects near thermostat housing, one routes from water pump area

Procedure

1. 1

   Drain cooling system
   Open the radiator drain petcock at the bottom passenger side of the radiator by turning counterclockwise. Allow coolant to drain into pan. If equipped with an engine block drain plug, open it as well to drain additional coolant. Collect drained coolant for proper disposal.
   Torque spec

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

   Remove air intake components
   Loosen the clamp securing the air intake tube to the throttle body. Disconnect the mass airflow sensor electrical connector. Remove the air intake tube assembly to gain access to the heater hoses at the rear of the engine. Set aside in a clean area.
3. 3

   Access heater inlet hose
   Locate the heater inlet hose at the rear passenger side of the engine near the thermostat housing. This hose routes from the engine to the firewall. Use needle nose pliers to squeeze and slide the hose clamp back along the hose, away from the connection point. Repeat for the firewall end of the hose.
4. 4

   Remove heater inlet hose
   Twist the hose back and forth while pulling to break the seal and remove from the engine fitting. Remove the opposite end from the firewall connection. Residual coolant will drain out - have shop towels ready. Inspect the metal fittings for corrosion or damage.
5. 5

   Access heater outlet hose
   Locate the heater outlet hose which connects from the firewall return line to the water pump or coolant crossover area on the driver side of the engine. Slide the hose clamps away from both connection points using pliers or a flathead screwdriver.
6. 6

   Remove heater outlet hose
   Twist and pull the heater outlet hose from both the firewall fitting and engine connection point. Allow residual coolant to drain. Inspect all connection points on the engine and firewall for debris, corrosion, or damage that could cause leaks.
7. 7

   Clean connection surfaces
   Use a wire brush or Scotch-Brite pad to clean the metal fittings on the engine and firewall where hoses connect. Remove any old coolant residue, corrosion, or rubber deposits. Wipe clean with shop towels. Ensure surfaces are smooth to prevent leaks with new hoses.
8. 8

   Install new heater inlet hose
   Place new constant tension hose clamps onto the new heater inlet hose before installation. Apply a small amount of coolant to the inside of the hose ends for lubrication. Push the hose firmly onto the engine fitting until it bottoms out, then install onto the firewall fitting. Ensure hose routing matches the original path without kinks or interference.
9. 9

   Secure inlet hose clamps
   Position the hose clamps approximately 1/2 inch from the end of each hose connection. Using a torque wrench with appropriate adapter or hose clamp tool, tighten the clamps to specification. Ensure clamps are positioned over the bead on the metal fittings.
   Torque spec

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

    Install new heater outlet hose
    Place new hose clamps onto the heater outlet hose. Lubricate hose ends with coolant and install onto the firewall return fitting first, then route to the engine connection point. Push firmly until fully seated on both ends. Verify routing clears any moving components or sharp edges.
11. 11

    Secure outlet hose clamps
    Position and torque the hose clamps on both ends of the outlet hose to specification, ensuring they are located over the beads on the metal fittings.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)
12. 12

    Close drain points
    Close the radiator drain petcock by turning clockwise and torquing to specification (hand tight). If an engine block drain plug was removed, reinstall it with a new seal washer and torque to specification.
    Torque spec

    Drain Petcock8 Nm (6 lb-ft)

    Coolant Drain Plug15 Nm (11 lb-ft)
13. 13

    Refill cooling system
    Mix Motorcraft Orange coolant with distilled water to achieve a 50/50 mixture (or use pre-mixed). Slowly fill the cooling system through the radiator cap or degas bottle until full. Start the engine and allow it to run at idle with the heater on maximum heat. Add coolant as the level drops while air purges from the system.
14. 14

    Bleed air and verify level
    With engine at operating temperature and heater blowing hot air, squeeze the upper radiator hose several times to help purge air pockets. Monitor coolant level and add as necessary. Allow engine to cool completely, then verify coolant level is at the COLD FILL line on the degas bottle. Top off if needed.

Reassembly

1. Reinstall air intake tube assembly and reconnect mass airflow sensor connector
2. Tighten intake tube clamp securely
3. Reinstall engine cover by aligning rear tabs first, then pressing down at front mounting points until it clicks into place
4. Wipe down engine bay and check for any tools or parts left behind

Verification

• Start engine and visually inspect all hose connections for coolant leaks while engine warms up
• Verify heater blows hot air at idle and during test drive
• Check coolant level in degas bottle after engine cools - should be at COLD FILL line
• Inspect ground beneath vehicle for any coolant drips after overnight parking
• Re-verify coolant level after 50-100 miles of driving and top off if necessary

More procedures for this vehicle