cooling

Radiator Cap

for 2015 Ford F-150 5.0L V8 Coyote · RWD

Editorial review:Chris Hackleman — Master Technician · 20+ years · Jeff Moore — Master Lexus & Toyota Mechanic · 20+ years

Difficulty

Easy

Time

6 min

Tools

Steps

✓Expert-verified. Personally reviewed and approved by OLP's master technicians (Chris Hackleman & Jeff Moore — 20+ years each). Always follow the vehicle's factory service information and torque specs.

This procedure covers the removal and replacement of the radiator cap on a 2015-2020 Ford F-150 with 5.0L V8 Coyote engine.

Warnings

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

⚠Wait at least 30 minutes after engine shutdown before opening the cooling system to allow pressure and temperature to decrease.

Tools required

Shop towel or ragEssential

Parts

Radiator cap × 1 — Motorcraft RS-540 or equivalent 16 PSI cap

Preparation

Ensure the engine is completely cold to the touch
Verify the vehicle is parked on level ground with the parking brake engaged
Open the hood and secure with the hood prop

Procedure

1
Locate the radiator cap
The radiator cap is located on top of the radiator tank at the front of the engine bay, driver's side. It is a black cap with the coolant warning symbol embossed on top.
2
Release system pressure
Place a shop towel over the radiator cap. Slowly turn the cap counterclockwise to the first stop (approximately 1/4 turn) and wait for any residual pressure to release. Listen for a hissing sound which indicates pressure escaping.
3
Remove the old radiator cap
Once pressure is fully released, press down on the cap while continuing to turn counterclockwise until it can be lifted off. Inspect the cap's rubber seals for cracks, deterioration, or hardening.
4
Inspect the radiator filler neck
Check the filler neck sealing surface for damage, corrosion, or debris. Clean the sealing surface with a shop towel if needed. Look for any signs of coolant leaks around the filler neck.
5
Install the new radiator cap
Align the new radiator cap with the filler neck tabs. Press down firmly and turn clockwise until it stops at the first detent, then continue turning while pressing down until it locks into the fully seated position. You should feel a positive click.

Reassembly

Ensure the radiator cap is fully seated and locked in position
Remove the shop towel and any tools from the engine bay

Verification

Visually confirm the radiator cap is properly seated and aligned
Start the engine and allow it to reach normal operating temperature while monitoring for leaks around the radiator cap
After the engine reaches operating temperature, turn it off and allow to cool, then verify the cap remains properly sealed with no coolant weeping

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