This procedure covers the removal and replacement of the radiator cap on a 2014 Ram 2500 with the 6.7L Cummins Diesel engine.

Warnings

Tools required

Parts

• Radiator cap × 1 — Use OEM specification - verify pressure rating matches original

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow engine to cool completely for at least 2 hours if recently operated
3. Open hood and secure with prop rod
4. Locate the radiator cap on top of the radiator at the front of the engine compartment

Procedure

1. 1

   Verify Engine is Cool
   Carefully touch the upper radiator hose to verify the engine has cooled sufficiently. The hose should be at ambient temperature. If warm or hot, wait longer before proceeding.
2. 2

   Relieve Pressure from Cooling System
   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 hissing sounds and wait until they stop completely.
3. 3

   Remove Old Radiator Cap
   After pressure is fully released, press down on the cap while continuing to turn counterclockwise until it can be lifted off. Remove the cap and set aside. Wipe the radiator filler neck with a clean shop towel to remove any debris or old gasket material.
4. 4

   Inspect Radiator Filler Neck
   Examine the radiator filler neck for cracks, damage, or corrosion. Check the sealing surface for any nicks or irregularities that could prevent proper cap sealing. If damage is present, the radiator or filler neck assembly may require replacement.
5. 5

   Inspect Old Cap
   Check the old radiator cap for a worn or cracked gasket, damaged spring, or corrosion. Verify the pressure rating stamped on the cap matches the specification (typically 16 PSI for this system). This helps confirm the correct replacement part.
6. 6

   Install New Radiator Cap
   Position the new radiator cap on the filler neck, aligning the cap with the neck opening. Press down firmly and turn clockwise until the cap locks into place with a positive click. The cap should sit flush and not be able to rotate further.
7. 7

   Verify Coolant Level
   With the cap removed or loosely installed, check the coolant level in the radiator. It should be visible at the base of the filler neck. If low, add Mopar OAT Coolant (Purple) to bring to proper level before final cap installation. Also verify coolant recovery reservoir is filled to the COLD mark.

Reassembly

1. Ensure radiator cap is fully seated and locked in place
2. Close hood securely

Verification

• Start engine and allow to warm to operating temperature while monitoring for leaks around the radiator cap
• Verify temperature gauge reads normal operating range
• After engine cools, recheck coolant level in both radiator and recovery reservoir
• Inspect for coolant weeping or staining around the cap sealing area
• Test drive vehicle and recheck for proper cooling system operation and no overheating

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