This procedure tests the cooling system for leaks using a pressure tester to identify failed gaskets, hoses, radiator, or water pump seals without disassembly.

Warnings

Tools required

Parts

• Radiator cap (if damaged or seal deteriorated) × 1 — Use OEM specification

Fluids

• Motorcraft Orange Coolant — 1 qt

Preparation

1. Ensure engine is completely cold to the touch before beginning work
2. Park vehicle on level surface and engage parking brake
3. Verify cooling system is filled to proper level - check coolant reservoir and add Motorcraft Orange coolant if low
4. Inspect radiator cap for cracks, damaged seal, or corrosion and replace if necessary
5. Have sufficient lighting available to inspect all cooling system components including underside hoses

Procedure

1. 1

   Access and inspect cooling system
   Open hood and visually inspect all accessible cooling system components. Check radiator hoses, heater hoses, thermostat housing, water pump weep hole (located on underside of water pump), radiator, and all hose clamps for obvious leaks, cracks, or coolant residue. On the 3.5L EcoBoost, pay special attention to the thermostat housing area and intercooler connections.
2. 2

   Remove radiator cap
   Ensure engine is cool, then slowly rotate the radiator cap counterclockwise to the first stop to release any residual pressure. Wait for any hissing to stop, then continue turning to remove the cap completely. Inspect the cap seal for cracks, deterioration, or damage. Set cap aside in clean area.
3. 3

   Check coolant level and condition
   Look into radiator filler neck and verify coolant is visible at the top. The coolant should be orange in color and relatively clear. If coolant is low, add Motorcraft Orange coolant to bring to proper level. If coolant appears rusty, contaminated, or has oil present, document this condition as it indicates a potential head gasket or oil cooler failure requiring further diagnosis.
4. 4

   Install pressure tester adapter
   Select the correct adapter from your pressure tester kit that fits the F-150 radiator neck (typically a Ford-specific adapter). Install the adapter onto the radiator filler neck, ensuring it seats completely and forms a proper seal. Thread or lock the adapter into place according to your tester's design.
5. 5

   Attach pressure tester
   Connect the pressure tester pump to the installed adapter. Ensure all connections are tight and secure. Verify the tester gauge reads zero before beginning to pump.
6. 6

   Pressurize cooling system
   Slowly pump the pressure tester to build pressure in the cooling system. Bring the system up to the pressure rating stamped on the radiator cap (typically 16 PSI for this vehicle). Do not exceed 20 PSI maximum. Monitor the gauge as you pump and stop once target pressure is reached.
   ⚠Pump slowly and watch pressure gauge closely. Rapid pressurization can damage plastic components or burst weak hoses suddenly.
7. 7

   Observe initial pressure hold
   Once at target pressure, stop pumping and observe the gauge for 2 minutes without touching the system. The pressure should hold steady with minimal drop (less than 2 PSI over 2 minutes is acceptable due to temperature changes). A rapid pressure drop indicates an active leak. Note the rate of pressure loss if any.
8. 8

   Inspect engine bay components
   While system is pressurized, carefully inspect all visible cooling system components in the engine bay. Check radiator tanks and core, upper and lower radiator hoses, heater hoses at firewall, thermostat housing, water pump area, overflow tank and cap, and all hose connections. Look for coolant seepage, drips, or spray. Use the flashlight to check areas behind the engine and under components.
9. 9

   Inspect underside components
   Move to the front underside of the vehicle and inspect lower radiator hose, water pump weep hole (located on bottom of water pump housing), lower radiator tanks, transmission cooler lines at radiator (if equipped), and oil cooler connections. The 3.5L EcoBoost water pump weep hole is accessed from below - any coolant dripping from this hole indicates water pump seal failure.
10. 10

    Check heater core circuit
    Inspect the heater hoses at the firewall and inside the vehicle at the floor (passenger side) for signs of coolant leakage. Place a shop towel under the heater core drain area inside the cabin if accessible. A leaking heater core will show wetness on carpet or drain coolant visibly when pressurized.
11. 11

    Monitor extended pressure hold
    Continue monitoring the pressure gauge for a total of 10-15 minutes while inspecting components. Re-pressurize as needed if pressure drops to maintain test pressure. Document total pressure loss over the test period. A properly sealed system should lose no more than 1-2 PSI over 15 minutes. Greater loss indicates a leak that requires repair even if not visually located.
12. 12

    Release pressure and remove tester
    Once testing is complete, slowly release pressure from the system using the tester's release valve. Allow pressure to drop to zero before disconnecting. Remove the pressure tester from the adapter, then remove the adapter from the radiator neck. Wipe any spilled coolant from the radiator and surrounding area.
13. 13

    Reinstall radiator cap and verify level
    Check coolant level in radiator and top off with Motorcraft Orange coolant if needed after pressure testing. Reinstall the radiator cap by pressing down and turning clockwise until it stops at the locked position. Verify the coolant reservoir is filled to the COLD FILL line.

Reassembly

1. No disassembly required for this procedure - radiator cap reinstallation completes the job
2. Wipe down any coolant spills on engine or radiator components to prevent false leak indicators during future inspections
3. If leaks were found, document location and severity for repair planning

Verification

• Start engine and allow to reach normal operating temperature while monitoring for leaks at any identified problem areas
• Verify coolant level remains stable in reservoir after engine reaches operating temperature
• Check that heater produces warm air, confirming no air pockets were introduced during testing
• Confirm no coolant puddles appear under vehicle after test drive
• Re-inspect any areas where leaks were detected during pressure test to verify they are active leaks
• If pressure test indicated loss but no leak was found visually, consider combustion leak test for head gasket issues or further inspection of internal components

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