cooling

Radiator Cap

for 2021 Ford F-150 3.5L V6 EcoBoost · 4WD

Difficulty

Easy

Time

6 min

Tools

Steps

This procedure covers the removal and replacement of the radiator cap on a 2021-2024 Ford F-150 with 3.5L V6 EcoBoost engine.

Warnings

⚠️Never remove the radiator cap when the engine is hot. The cooling system is pressurized and can spray boiling coolant causing severe burns.

⚠Always allow the engine to cool completely before removing the radiator cap, at least 30 minutes after shutdown.

Shop towel or ragEssential

Coolant catch pan

Ensure the engine has been off for at least 30 minutes and is completely cool to the touch
Open the hood and secure it in the open position
Locate the radiator cap on top of the radiator assembly at the front of the engine bay

1
Verify Engine Temperature
Touch the upper radiator hose with the back of your hand to confirm the cooling system is cool. If the hose feels warm or hot, wait longer before proceeding.
2
Release Pressure
Place a shop towel over the radiator cap. Slowly turn the cap counterclockwise to the first stop position (approximately 1/4 turn) and pause to allow any residual pressure to escape. Listen for a hissing sound indicating pressure release.
3
Remove Radiator Cap
Once pressure is fully released and no hissing is heard, press down on the cap while continuing to turn counterclockwise until it can be lifted off. Remove the cap and set it aside.
4
Inspect Old Cap and System
Examine the old radiator cap for signs of damage, cracks, or deteriorated rubber seals. Check the radiator filler neck for damage or debris. Visually inspect the coolant level in the radiator.
5
Install New Radiator Cap
Align the new radiator cap with the filler neck. Press down firmly and turn clockwise until it stops at the first detent, then continue pressing and turning until it locks into the fully seated position. You should feel a positive click or stop.
6
Verify Installation
Ensure the radiator cap is fully seated and locked by attempting to turn it further clockwise. The cap should not turn beyond its locked position. Visually confirm proper alignment and seating.

Start the engine and allow it to warm to normal operating temperature while monitoring for coolant leaks around the radiator cap
After the engine reaches operating temperature, shut it off and allow it to cool completely, then verify the cap remains properly seated
Check coolant level in the overflow reservoir and top off if necessary with Motorcraft Orange Coolant to the COLD FILL mark