This procedure covers the removal and replacement of the radiator on a 2012-2018 Jeep Wrangler JK with the 3.6L V6 engine, including coolant drain, transmission cooler line disconnect, and refill procedures.

Warnings

Tools required

Parts

• Radiator assembly × 1 — Use OEM specification for direct fit
• Transmission cooler line O-rings × 2 — Mopar 68078356AA or equivalent
• Radiator cap (if damaged) × 1 — Mopar 68004015AA
• Hose clamps (if damaged) × 4 — Replace as needed

Fluids

• Mopar OAT Coolant (Purple) — 13 qt

Preparation

1. Ensure engine is completely cold (not driven for minimum 2 hours)
2. Park vehicle on level ground and engage parking brake
3. Disconnect negative battery cable to prevent fan clutch engagement
4. Remove engine cover by pulling upward on front edge and lifting off mounting grommets
5. Place large drain pan (minimum 2 gallon capacity) under radiator drain petcock
6. Have secondary drain pan available for transmission fluid from cooler lines

Procedure

1. 1

   Drain cooling system
   Open radiator petcock at bottom driver side of radiator by turning counterclockwise. Allow coolant to drain completely into drain pan. Once drained, hand-tighten petcock to prevent loss during radiator removal. Remove radiator cap to allow complete drainage.
   Torque spec

   Drain Petcock5 Nm (4 lb-ft)
2. 2

   Remove upper radiator hose
   Locate upper radiator hose connecting radiator to thermostat housing on passenger side of engine. Use pliers to compress and slide hose clamp away from radiator neck. Twist hose gently to break seal, then pull off radiator fitting. Residual coolant will drain.
3. 3

   Remove lower radiator hose
   Access lower radiator hose from underneath vehicle (raise and support if needed for access). Compress hose clamp and slide away from radiator fitting. Twist and pull hose off lower radiator outlet. Allow residual coolant to drain into pan.
   Torque spec

   Upper/Lower Hose Clamps3 Nm (2 lb-ft)
4. 4

   Disconnect transmission cooler lines
   Locate two transmission cooler lines on passenger side of radiator (vehicles with automatic transmission). Position drain pan under connections. Use flare nut wrench to loosen fittings at radiator. Turn counterclockwise and remove lines completely. Cap open lines with clean rags to prevent contamination. Note orientation of lines for reinstallation.
   ⚠Do not use standard open-end wrench on transmission cooler fittings as this will round off the soft aluminum fittings. Use proper flare nut wrench only.
   Torque spec

   Transmission Cooler Lines25 Nm (18 lb-ft)
5. 5

   Remove fan shroud upper mounting bolts
   Locate two upper fan shroud mounting bolts at top of radiator. Remove bolts using appropriate socket. Leave lower shroud mounting points attached - shroud will rest on fan during radiator removal.
6. 6

   Disconnect auxiliary components
   Disconnect any auxiliary connections to radiator: coolant overflow hose from radiator neck (passenger side), and engine oil cooler lines if equipped. Mark or photograph connections for proper reassembly. For overflow hose, simply pull off barbed fitting.
7. 7

   Remove radiator mounting bolts
   Locate four radiator mounting bolts - two at upper corners of radiator core support and two lower mounts accessible from above. Remove all four bolts completely. Support radiator with one hand while removing final bolt.
   ⚠Radiator is top-heavy when removed. Support radiator core while removing final mounting bolt to prevent dropping.
   Torque spec

   Radiator Mount Bolts12 Nm (9 lb-ft)
8. 8

   Remove radiator assembly
   Carefully lift radiator straight up and out of engine bay. Tilt top of radiator toward engine slightly to clear fan shroud and condenser. Guide transmission cooler line fittings through core support opening. Set radiator on protected work surface with fittings facing up to prevent damage.
   ⚠Aluminum radiator core and plastic tanks are fragile. Do not set radiator on hard surface without protection. Keep radiator upright to prevent internal baffle damage.
9. 9

   Inspect and clean mounting area
   Inspect radiator mounting brackets and rubber isolators for damage or deterioration. Replace any damaged isolators. Clean debris from radiator mounting area and core support. Inspect condenser (AC radiator) for damage. Check fan shroud for cracks.
10. 10

    Prepare new radiator
    Remove shipping caps from new radiator fittings. Install new O-rings on transmission cooler line fittings (lubricate with small amount of ATF+4). Verify drain petcock is closed hand-tight. Compare new radiator to old unit to verify correct application and fitting locations.
    ℹ️New O-rings on transmission cooler fittings are critical to prevent leaks. Never reuse old O-rings.
    Torque spec

    Drain Petcock5 Nm (4 lb-ft)
11. 11

    Install radiator assembly
    Carefully lower new radiator into position, guiding transmission cooler fittings through core support opening first. Align radiator onto lower mounting isolators. Ensure radiator sits flush against all four rubber mounting isolators before installing bolts. Verify fan shroud is properly positioned behind radiator.
    Torque spec

    Radiator Mount Bolts12 Nm (9 lb-ft)
12. 12

    Reconnect transmission cooler lines
    Thread transmission cooler line fittings into radiator by hand until seated. Verify correct line routing matches original configuration. Tighten fittings to specification using flare nut wrench. Do not overtighten as this will damage aluminum threads.
    ⚠Cross-threading transmission cooler fittings will destroy the radiator. Thread fittings by hand first to ensure proper engagement before using wrench.
    Torque spec

    Transmission Cooler Lines25 Nm (18 lb-ft)
13. 13

    Install fan shroud and hoses
    Reinstall upper fan shroud mounting bolts to secure shroud to radiator. Install lower radiator hose onto fitting, ensuring hose is fully seated on barbed fitting. Position hose clamp over hose and tighten to specification. Repeat for upper radiator hose. Reconnect coolant overflow hose to radiator neck fitting.
    Torque spec

    Upper/Lower Hose Clamps3 Nm (2 lb-ft)
14. 14

    Refill cooling system
    Mix Mopar OAT coolant 50/50 with distilled water or use pre-mixed coolant. Slowly fill radiator through radiator neck until coolant reaches bottom of filler neck. Fill coolant overflow reservoir to COLD MAX line. Install radiator cap. Start engine and allow to reach operating temperature with heater on MAX heat. Monitor coolant level and add as needed. Check for leaks at all connections.
    ℹ️3.6L V6 cooling system may require burping procedure. Run engine at 2000 RPM for 30 seconds several times to purge air pockets. Coolant level will drop as air is expelled.
15. 15

    Check transmission fluid level
    With vehicle on level ground and engine at operating temperature, check automatic transmission fluid level (transmission in PARK). Add ATF+4 as needed to compensate for fluid lost during cooler line disconnect. Typical loss is 1-2 quarts. Verify no leaks at transmission cooler line connections.
    ℹ️Transmission fluid level must be checked with engine running and transmission at operating temperature. Refer to dipstick markings for proper hot level.

Reassembly

1. Reinstall engine cover by aligning grommets with mounting posts and pressing down firmly
2. Reconnect negative battery cable
3. Top off coolant overflow reservoir to COLD MAX line after engine cools completely
4. Verify radiator cap is properly seated and locked

Verification

• Start engine and verify no coolant leaks at radiator hoses, petcock, or transmission cooler fittings
• Allow engine to reach full operating temperature (thermostat open) and verify upper radiator hose becomes hot
• Check that cooling fan cycles on and off properly as engine reaches temperature
• Verify heater produces hot air at idle and under acceleration
• Monitor coolant level in overflow reservoir - should be at COLD MAX when engine is cold
• Check transmission fluid level with engine at operating temperature - add ATF+4 as needed
• Test drive vehicle and monitor temperature gauge - should remain in normal range
• Recheck all connections for leaks after test drive and overnight cold soak

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