Complete coolant system flush and refill for the 3.5L EcoBoost engine, including draining old coolant, flushing the system, and refilling with Motorcraft Orange Coolant to maintain optimal engine temperatures and prevent corrosion.

Warnings

Tools required

Parts

• Radiator drain plug gasket × 1 — Use OEM specification

Fluids

• Motorcraft Orange Coolant — 13 qt

Preparation

1. Ensure engine is completely cold (not run for at least 2 hours)
2. Park vehicle on level surface and engage parking brake
3. Remove engine cover by pulling upward on both sides to release clips
4. Place drip cloths or cardboard under radiator area to catch spills
5. Locate the degas bottle (coolant reservoir) on passenger side of engine bay
6. Slowly remove degas bottle cap to release any residual pressure

Procedure

1. 1

   Drain coolant from radiator
   Locate the radiator drain plug on the driver side lower corner of the radiator. Place drain pan underneath. Remove the drain plug and allow coolant to drain completely. Remove the old gasket from the drain plug and inspect threads for damage.
   Torque spec

   Block Drain Plug25 Nm (18 lb-ft)
2. 2

   Drain coolant from engine block
   Locate the engine block drain on the rear of the engine block, accessible from underneath near the transmission bellhousing on the driver side. Remove the drain plug and allow additional coolant to drain. This ensures complete drainage from the engine block.
   ℹ️Block drain may be difficult to access. You may need to work from underneath the vehicle for better reach.
   Torque spec

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

   Flush cooling system (optional but recommended)
   If performing a complete flush, reinstall both drain plugs hand-tight with new gaskets. Fill the system with distilled water through the degas bottle. Start the engine and run until operating temperature is reached (thermostat opens), then allow to cool completely. Repeat drain process. This removes remaining old coolant and contaminants.
   ⚠Only run engine for flushing if drain plugs are properly installed. Monitor temperature gauge to prevent overheating during flush cycle.
4. 4

   Install radiator drain plug
   Install a new drain plug gasket onto the radiator drain plug. Thread the drain plug in by hand until seated, then torque to specification. Ensure the plug is not cross-threaded.
   Torque spec

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

   Install engine block drain plug
   Install the engine block drain plug with new gasket if available. Thread in by hand until seated, then torque to specification.
   Torque spec

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

   Locate and open bleed screw
   Locate the cooling system bleed screw on the thermostat housing or upper coolant crossover tube near the front of the engine. Open the bleed screw approximately 2-3 turns. This will be left open during the filling process to allow air to escape.
   ℹ️The bleed screw location may vary slightly. Look for a small bolt or valve on the highest point of the cooling system.
   Torque spec

   Bleed Screw8 Nm (6 lb-ft)
7. 7

   Fill cooling system with new coolant
   Using a funnel, slowly pour Motorcraft Orange Coolant into the degas bottle. Fill slowly to allow air to escape through the open bleed screw. Watch the bleed screw until coolant flows out steadily without air bubbles, then close the bleed screw to specification. Continue filling the degas bottle to the COLD FILL MAX line. Install degas bottle cap.
   ℹ️Fill process may take 10-15 minutes. Rushing can trap air in the system. If available, use a vacuum fill tool to eliminate air pockets more effectively.
   Torque spec

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

   Initial engine run and burp procedure
   Start the engine and allow it to idle. Turn the heater to maximum heat and fan to high speed. Watch the temperature gauge and listen for normal cooling fan operation. Run until the engine reaches normal operating temperature (approximately 190-200°F). Monitor the degas bottle level and add coolant as needed as the thermostat opens.
   ⚠Watch temperature gauge closely. If temperature rises above normal or warning light illuminates, shut off engine immediately and investigate for air pockets or leaks.
9. 9

   Allow engine to cool and recheck level
   Shut off the engine and allow it to cool completely (at least 1 hour). Once cool, check the degas bottle level and top off to the COLD FILL MAX line if needed. This accounts for coolant that filled voids as air was purged from the system.
10. 10

    Final bleed and verification
    Start the engine again and repeat the warm-up cycle. Check for leaks at the radiator drain plug, block drain plug, and bleed screw. Verify heat output from heater vents is strong and consistent. Allow to cool and verify final coolant level is at COLD FILL MAX line on degas bottle.

Reassembly

1. Reinstall engine cover by aligning clips and pressing down firmly until all clips engage
2. Clean any coolant residue from engine bay components and frame
3. Dispose of old coolant at an approved recycling facility - do not pour down drains

Verification

• Verify degas bottle coolant level is at COLD FILL MAX line with engine cold
• Check for any coolant leaks under vehicle and around all drain points
• Start engine and verify heater produces hot air on both driver and passenger sides
• Confirm engine reaches normal operating temperature (approximately 190-200°F) and cooling fans cycle on/off properly
• After first drive cycle, recheck coolant level when cold and top off if needed
• Monitor coolant level over next few days and top off as system fully stabilizes

More procedures for this vehicle