This procedure covers the removal and replacement of the lower radiator hose on a 2012-2018 Jeep Wrangler with the 3.6L V6 engine, including coolant drainage and refill.

Warnings

Tools required

Parts

• Lower radiator hose × 1 — Use OEM specification
• Hose clamps (if reusing old clamps is not advisable) × 2 — Use OEM specification

Fluids

• Mopar OAT Coolant (Purple) — 13 qt

Preparation

1. Ensure engine is completely cool (at least 2 hours after last operation)
2. Park vehicle on level ground and engage parking brake
3. Place drain pan under radiator drain petcock location
4. Remove engine cover by pulling upward on cover; it is retained by rubber grommets
5. Locate lower radiator hose connection points at radiator (driver side lower) and water pump/engine block

Procedure

1. 1

   Drain cooling system
   Slowly rotate the radiator cap counterclockwise to release any residual pressure, then remove completely. Locate the drain petcock on the driver side lower radiator tank. Open the petcock by turning counterclockwise and allow coolant to drain into the drain pan. Once drained, close the petcock hand-tight to the specified torque.
   Torque spec

   Drain Petcock8 Nm (6 lb-ft)
2. 2

   Remove lower hose clamp at radiator
   Locate the hose clamp securing the lower radiator hose to the radiator outlet (driver side lower tank). Using a flathead screwdriver or hose clamp pliers, loosen the clamp by turning the screw counterclockwise or squeezing the spring clamp tabs. Slide the clamp away from the radiator connection point along the hose.
3. 3

   Disconnect hose from radiator
   Firmly grasp the lower radiator hose near the radiator connection and twist while pulling to break the seal. Pull the hose straight off the radiator outlet neck. If the hose is stuck, use a gentle twisting motion. Do not pry against the radiator plastic tank as it may crack.
4. 4

   Remove lower hose clamp at engine
   Locate the hose clamp at the engine side connection point (typically at the water pump inlet on the passenger side of the engine). Loosen the clamp using a flathead screwdriver or hose clamp pliers and slide it away from the connection point along the hose.
   ℹ️Access may be limited. You may need to reach from below or use an extension on your screwdriver for better access to the engine-side clamp.
5. 5

   Remove lower radiator hose
   Twist and pull the hose off the engine water pump inlet connection. Remove the hose completely from the vehicle. Allow any remaining coolant to drain into the pan. Inspect both connection points on the radiator and water pump for damage, cracks, or corrosion.
6. 6

   Prepare new hose and install at engine
   If reusing clamps, slide them onto the new lower radiator hose in the correct orientation (screw accessible). If using new clamps, position them on the hose. Clean the water pump inlet connection with a shop towel. Apply a thin film of fresh coolant to the inside of the hose end and the water pump inlet to aid installation. Push the hose firmly onto the water pump inlet until it seats completely against the bead on the inlet neck.
   ℹ️Ensure the hose is routed properly without kinks or sharp bends. The hose should follow the original path and not contact any sharp edges or moving components.
7. 7

   Install engine-side hose clamp
   Slide the hose clamp into position over the connection point, ensuring it is positioned past the bead on the water pump inlet neck. Tighten the clamp to the specified torque. Verify the hose cannot be pulled off the connection.
   Torque spec

   Hose Clamps4 Nm (3 lb-ft)
8. 8

   Install hose at radiator
   Clean the radiator outlet neck with a shop towel. Apply a thin film of fresh coolant to the inside of the hose end and the radiator outlet. Push the hose firmly onto the radiator outlet until it seats completely against the bead on the outlet neck.
9. 9

   Install radiator-side hose clamp
   Slide the hose clamp into position over the radiator connection point, ensuring it is positioned past the bead on the radiator outlet neck. Tighten the clamp to the specified torque. Verify the hose is secure and cannot be pulled off.
   Torque spec

   Hose Clamps4 Nm (3 lb-ft)
10. 10

    Refill cooling system
    Using a funnel, slowly pour Mopar OAT Purple coolant into the radiator fill neck. Fill until coolant reaches the bottom of the fill neck. Slowly pour coolant into the coolant recovery reservoir until it reaches the MAX cold fill line. Allow time for air to escape during filling.
11. 11

    Burp cooling system
    With the radiator cap still off, start the engine and allow it to idle. Turn the heater to maximum heat and fan speed. As the engine warms, coolant level will drop as the thermostat opens and air purges from the system. Continue adding coolant to maintain level at the bottom of the fill neck. Run until the engine reaches normal operating temperature and the cooling fans cycle on.
    ⚠Monitor the temperature gauge during this process. If the gauge approaches the red zone, shut off the engine immediately and allow it to cool before continuing.
12. 12

    Final fill and cap installation
    Once the cooling fans have cycled and no more air bubbles emerge from the radiator, top off the radiator to the bottom of the fill neck. Install the radiator cap by aligning the tabs and rotating clockwise until it locks. Verify the coolant recovery reservoir is at the MAX cold fill line and adjust if necessary. Shut off the engine.

Reassembly

1. Reinstall engine cover by aligning rubber grommets with ball studs on engine and pressing down firmly until seated
2. Wipe up any spilled coolant from engine and frame components
3. Double-check all hose clamps are tight and hoses are properly seated

Verification

• With engine cool, verify coolant level in reservoir is at MAX cold fill line
• Start engine and allow to reach operating temperature while monitoring for leaks at both hose connections
• Check for any coolant drips or wet spots at the lower radiator hose connections
• Verify temperature gauge reads in normal range and cooling fans cycle on/off properly
• After test drive, recheck coolant level when engine is cool and top off if necessary
• Inspect under vehicle for any coolant drips or puddles after 24 hours of normal operation

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