Replace the coolant temperature sensor on a 2015-2020 Ford F-150 3.5L EcoBoost engine to restore accurate temperature readings and proper engine management.

Warnings

Tools required

Parts

• Coolant temperature sensor × 1 — Motorcraft DY-1177 or equivalent
• Coolant temperature sensor O-ring × 1 — Usually included with sensor

Fluids

• Motorcraft Orange Coolant — 1.5 qt

Preparation

1. Ensure engine is completely cold to the touch (minimum 2 hours after last operation)
2. Park vehicle on level surface and engage parking brake
3. Disconnect negative battery cable to prevent fault codes during sensor disconnection
4. Locate coolant temperature sensor on driver's side of engine block, below and behind the turbocharger assembly

Procedure

1. 1

   Drain partial coolant
   Place drain pan under the radiator drain petcock on the driver's side lower radiator tank. Open the drain petcock by turning counterclockwise and drain approximately 1-2 quarts of coolant until the level drops below the sensor location on the engine block. Close drain petcock hand tight.
   Torque spec

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

   Access coolant temperature sensor
   From the driver's side of the engine bay, locate the coolant temperature sensor on the engine block below the turbocharger. The sensor is positioned near the rear of the block with a two-pin electrical connector. You may need to reach down from above or access from underneath the vehicle for better visibility.
3. 3

   Disconnect electrical connector
   Press the locking tab on the sensor electrical connector and pull straight out to disconnect. Use a small pick if needed to release the locking tab. Inspect connector terminals for corrosion or damage.
4. 4

   Remove coolant temperature sensor
   Using a 19mm deep socket with extension, carefully loosen and remove the coolant temperature sensor by turning counterclockwise. Be prepared for minor coolant spillage. Remove the sensor completely and inspect the O-ring sealing surface in the engine block for debris or damage.
   ⚠Some residual coolant will drain from the sensor bore. Keep drain pan positioned to catch spillage.
5. 5

   Prepare new sensor
   Inspect the new coolant temperature sensor and verify the O-ring is properly seated in the sensor groove. Lightly lubricate the O-ring with clean coolant to ease installation. Clean the sensor bore in the engine block with a shop towel to ensure proper seating.
6. 6

   Install new sensor
   Thread the new coolant temperature sensor into the engine block by hand, turning clockwise until it seats against the block. Tighten to finger-tight plus 1/4 turn (approximately 15-20 Nm). Do not over-torque as the sensor housing is plastic and can crack.
   ⚠The sensor housing is plastic. Use moderate torque only - over-tightening will crack the sensor body.
7. 7

   Reconnect electrical connector
   Push the electrical connector onto the new sensor until you hear and feel the locking tab click into place. Gently tug on the connector to verify it is secured.
8. 8

   Refill coolant system
   Using a funnel at the degas bottle (coolant reservoir), add Motorcraft Orange Coolant to restore the level to the COLD FILL mark. Start with approximately 1-1.5 quarts. Do not overfill.
9. 9

   Bleed cooling system
   Start the engine and allow it to reach normal operating temperature with the degas bottle cap removed. Monitor coolant level and add as needed. Run engine until the cooling fans cycle on, then turn off and allow to cool. Recheck coolant level when cold and top off to COLD FILL mark if necessary.
10. 10

    Reconnect battery and clear codes
    Reconnect the negative battery cable. Start the engine and verify no check engine light or temperature warning indicators. If a fault code was stored, it should clear after several drive cycles or can be cleared with a scan tool.

Reassembly

1. Ensure all electrical connections are fully seated and locked
2. Verify drain petcock is closed hand tight before refilling coolant
3. Double-check coolant level at degas bottle after engine cools completely

Verification

• Start engine and verify temperature gauge rises to normal operating range (approximately halfway)
• Check for coolant leaks around the sensor location with engine at operating temperature
• Verify no check engine light or temperature warning messages on instrument cluster
• Confirm cooling fans cycle on and off normally during warm-up
• Recheck coolant level after first drive cycle when engine is cold

More procedures for this vehicle