This procedure covers the removal and replacement of the coolant bypass pipe on the 5.0L Coyote V8 engine, which connects the water pump to the thermostat housing and commonly fails due to corrosion or cracking.

Warnings

Tools required

Parts

• Coolant bypass pipe assembly × 1 — Use OEM Ford coolant bypass pipe
• Thermostat housing gasket or O-ring × 1 — Replace if integrated with bypass pipe
• Hose clamps × 2 — Replace if corroded or damaged

Fluids

• Motorcraft Orange Coolant — 4 qt

Preparation

1. Ensure engine is completely cold to the touch (minimum 2 hours since last operation)
2. Park vehicle on level surface and engage parking brake
3. Disconnect negative battery terminal to prevent accidental fan activation
4. Remove engine cover by pulling upward on all four corners
5. Place drain pan under radiator drain petcock

Procedure

1. 1

   Drain cooling system
   Open the radiator drain petcock at the bottom passenger side of the radiator and allow coolant to drain into pan. Remove radiator cap to speed draining. If vehicle has coolant drain plug on engine block, open it as well for more complete drainage.
   Torque spec

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

   Remove air intake components
   Disconnect the air intake tube from the throttle body. Loosen the hose clamp at the throttle body and remove the entire intake tube assembly to improve access to the front of the engine. Set aside in a clean area.
3. 3

   Disconnect upper radiator hose
   Locate the upper radiator hose connection at the thermostat housing on the driver side front of the engine. Use hose clamp pliers to compress and slide the spring clamp back approximately 2 inches. Twist the hose to break the seal, then pull it off the thermostat housing outlet.
4. 4

   Remove coolant bypass hose
   Identify the coolant bypass hose that connects to the bypass pipe. This runs from the water pump area to the thermostat housing. Use hose clamp pliers to release the clamps at both ends. Remove the hose and inspect for deterioration.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
5. 5

   Disconnect heater hose connections
   Locate the heater hose connections on the bypass pipe. There are typically two heater hoses that connect to fittings on the bypass pipe assembly. Use hose clamp pliers to release the clamps and carefully pull the hoses off the fittings. Be prepared for residual coolant spillage.
   ℹ️Mark or photograph heater hose routing before removal to ensure correct reinstallation.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
6. 6

   Remove thermostat housing bolts
   Remove the bolts securing the thermostat housing to the engine. There are typically three 8mm bolts. Keep track of bolt locations as they may be different lengths. The housing does not need to be fully removed, just loosened enough to access the bypass pipe connection.
   Torque spec

   Housing Bolts17 Nm (13 lb-ft)
7. 7

   Remove bypass pipe mounting bolts
   Locate and remove the housing bolts that secure the coolant bypass pipe to the water pump and front cover. There are typically 2-3 bolts depending on the specific bypass pipe design. Use a 10mm socket and be careful not to drop bolts into the engine bay.
   Torque spec

   Housing Bolts17 Nm (13 lb-ft)
8. 8

   Remove coolant bypass pipe
   Carefully work the bypass pipe assembly out of its mounting position. It may require gentle twisting and maneuvering to clear surrounding components. The pipe has O-rings or gaskets at connection points that may stick. Use a small pry tool if necessary, being careful not to damage sealing surfaces on the water pump or thermostat housing.
   ⚠Do not pry against aluminum sealing surfaces. Damage to these surfaces can cause leaks that require water pump or housing replacement.
9. 9

   Clean sealing surfaces
   Thoroughly clean all sealing surfaces on the water pump, thermostat housing, and engine front cover where the bypass pipe mounts. Remove all old gasket material and O-ring residue using a plastic scraper. Wipe surfaces clean with shop towels. Inspect for cracks, corrosion, or damage.
10. 10

    Install new bypass pipe
    Lightly lubricate new O-rings on the replacement bypass pipe with fresh coolant. Carefully align the bypass pipe into position, ensuring O-rings seat properly in their grooves. Start all mounting bolts by hand to ensure proper threading before tightening.
11. 11

    Torque bypass pipe and housing bolts
    Using a torque wrench, tighten the bypass pipe housing bolts to specification. Then reinstall and torque the thermostat housing bolts. Ensure all connections are properly seated before final torquing.
    Torque spec

    Housing Bolts17 Nm (13 lb-ft)
12. 12

    Reconnect all hoses
    Reinstall the heater hoses to the bypass pipe fittings and secure with new or existing clamps. Reconnect the bypass hose between the water pump and thermostat housing. Install the upper radiator hose to the thermostat housing. Ensure all hose clamps are positioned properly and tightened to specification.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)
13. 13

    Refill cooling system
    Close the radiator drain petcock and any engine block drain plugs, torquing to specification. Fill the cooling system slowly through the radiator cap opening with Motorcraft Orange Coolant (50/50 premix or properly mixed concentrate). Fill until coolant reaches the base of the filler neck. If equipped, open the bleed screw on the thermostat housing or upper coolant crossover to allow air to escape during filling.
    Torque spec

    Drain Petcock8 Nm (6 lb-ft)

    Bleed Screw8 Nm (6 lb-ft)
14. 14

    Bleed cooling system
    With the bleed screw open, continue adding coolant until air-free coolant flows from the bleed point. Close the bleed screw to specification. Install the radiator cap. Start the engine and allow it to reach operating temperature with the heater on maximum heat. Monitor coolant level and add as needed. Run engine through several heat cycles, checking for leaks at all bypass pipe connections.
    ⚠Keep hands away from cooling fans which may activate at any time once the engine is running.
    Torque spec

    Bleed Screw8 Nm (6 lb-ft)

Reassembly

1. Reinstall air intake tube assembly and secure all clamps
2. Reinstall engine cover
3. Reconnect negative battery terminal
4. Top off coolant reservoir to MAX line with Motorcraft Orange Coolant
5. Check under vehicle for any coolant drips or leaks

Verification

• Start engine and verify no coolant leaks from bypass pipe connections, thermostat housing, or hose clamps
• Confirm engine reaches normal operating temperature (approximately 195-220°F) without overheating
• Verify heater produces hot air on maximum setting, indicating proper coolant flow
• Check coolant level in reservoir after engine cools - should be at MAX line when cold
• Inspect work area under hood for proper hose routing and no loose components
• Perform test drive and recheck for leaks and proper temperature operation

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