Complete coolant system drain, flush, and refill procedure for the 2021-2024 Ford F-150 3.5L EcoBoost V6, removing old coolant and replacing with fresh Motorcraft Orange coolant to maintain optimal engine temperature control.

Warnings

Tools required

Parts

• Radiator drain plug seal/washer × 1 — Use OEM specification

Fluids

• Motorcraft Orange Coolant — 13 qt

Preparation

1. Ensure engine is completely cold to the touch
2. Park vehicle on level ground and engage parking brake
3. Place drain pan beneath radiator drain location on passenger side of radiator
4. Open hood and locate radiator cap on driver side of engine bay
5. Verify you have correct Motorcraft Orange coolant premixed or distilled water for mixing to 50/50 ratio

Procedure

1. 1

   Release cooling system pressure
   Slowly rotate the radiator cap counterclockwise to the first detent and allow any residual pressure to vent. Wait 10 seconds, then continue rotating to remove the cap completely. Set cap aside on clean surface.
2. 2

   Drain coolant from radiator
   Locate the radiator drain plug at the bottom passenger side of the radiator. Position drain pan directly underneath. Using appropriate socket, loosen and remove the drain plug and seal washer. Allow coolant to drain completely into pan (approximately 10-15 minutes). Inspect the seal washer and replace if damaged or compressed.
   Torque spec

   Block Drain Plug25 Nm (18 lb-ft)
3. 3

   Drain engine block coolant
   Locate the coolant bleed screw on top of the engine near the thermostat housing on the driver side. Using appropriate socket, open the bleed screw by turning counterclockwise 2-3 turns to allow engine block coolant to drain through the radiator drain. Leave bleed screw open during this step.
   Torque spec

   Bleed Screw8 Nm (6 lb-ft)
4. 4

   Flush cooling system (optional but recommended)
   Once draining stops, reinstall radiator drain plug with new or inspected seal washer to specified torque. Close bleed screw finger tight temporarily. Fill system with distilled water through radiator opening. Start engine and run at idle with heater on maximum heat for 5 minutes. Shut off engine, allow to cool 30 minutes, then drain again following steps 2-3. Repeat if old coolant was heavily contaminated.
   Torque spec

   Block Drain Plug25 Nm (18 lb-ft)
5. 5

   Reinstall drain plug
   Clean the radiator drain plug threads and sealing surface. Install new or inspected seal washer onto drain plug. Thread drain plug into radiator by hand until seated, then tighten to specified torque using torque wrench.
   Torque spec

   Block Drain Plug25 Nm (18 lb-ft)
6. 6

   Begin coolant fill
   Ensure bleed screw remains open. Using funnel, slowly pour Motorcraft Orange coolant into the radiator filler neck. Fill slowly to prevent air pockets. Continue filling until coolant flows steadily from the open bleed screw without air bubbles.
7. 7

   Close bleed screw and complete fill
   Once coolant flows steadily from bleed screw, close the bleed screw to specified torque. Continue filling radiator to approximately 1 inch below the filler neck. Do not overfill.
   Torque spec

   Bleed Screw8 Nm (6 lb-ft)
8. 8

   Fill coolant reservoir
   Locate the coolant overflow reservoir on the passenger side of the engine bay. Fill reservoir to the COLD FILL MAX line with Motorcraft Orange coolant. Do not exceed this line.
9. 9

   Purge air from system
   Install radiator cap hand tight. Start engine and allow to run at idle. Turn heater to maximum temperature and fan speed. Allow engine to warm up to normal operating temperature (approximately 10-15 minutes). Monitor temperature gauge to ensure it reaches normal range and cooling fans cycle on. Observe for leaks around drain plug and bleed screw.
   ⚠Monitor temperature gauge closely. If temperature exceeds normal range, shut off engine immediately and recheck for air pockets or leaks.
   Torque spec

   Radiator Cap1 Nm (1 lb-ft)
10. 10

    Final coolant level adjustment
    Shut off engine and allow to cool for at least 30 minutes. Check coolant level in overflow reservoir - it should be between COLD FILL MIN and MAX lines. Add coolant to overflow reservoir if needed. Remove radiator cap and check radiator fill level - top off if more than 1 inch below filler neck. Reinstall radiator cap hand tight.
    Torque spec

    Radiator Cap1 Nm (1 lb-ft)

Reassembly

1. Ensure radiator cap is properly seated and hand tight
2. Verify coolant overflow reservoir is filled to COLD FILL MAX line
3. Wipe down any coolant spills from engine bay and chassis components
4. Properly dispose of old coolant at recycling facility or auto parts store

Verification

• Start engine and verify no coolant leaks from drain plug, bleed screw, or hose connections
• Confirm temperature gauge reaches normal operating range without overheating
• Verify heater produces hot air at idle and at 2000 RPM
• Check coolant overflow reservoir level after 24 hours of driving - should remain between MIN and MAX lines
• Use coolant refractometer to verify 50/50 mixture providing freeze protection to -34°F (-37°C)
• Test drive vehicle and monitor temperature gauge remains in normal range under load

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