Complete removal and reinstallation of the 3.6L Pentastar V6 engine from a 2012-2018 Jeep Wrangler JK, including disconnection of all electrical, fuel, cooling, and drivetrain components.

Warnings

Tools required

Parts

• Engine oil filter × 1 — MO-090
• Engine oil drain plug gasket × 1 — Use OEM specification
• Coolant hose clamps (assorted) × 1 — Replace as needed
• Exhaust manifold gaskets × 2 — Use OEM specification
• Transmission-to-engine mounting bolts × 1 — Use OEM specification
• Engine mount hardware × 1 — Inspect and replace if damaged
• Intake manifold gaskets × 1 — Use OEM specification

Fluids

• Mopar 5W-20 Synthetic Blend engine oil — 6.5 qt
• Mopar OAT Coolant (Purple) — 13 qt
• Mopar ATF+4 — 1 qt

Preparation

1. Park vehicle on level, solid surface and engage parking brake. Chock rear wheels.
2. Disconnect negative battery cable, then positive cable. Remove battery and battery tray for working clearance.
3. Remove hood by marking hinge positions and removing hinge bolts with assistant support.
4. Relieve fuel system pressure by removing fuel pump fuse and running engine until it stalls, then crank for 5 seconds.
5. Drain engine coolant by opening radiator petcock and removing upper radiator cap. Capture coolant in appropriate container.
6. Drain engine oil and remove oil filter. Capture oil in drain pan rated for capacity.
7. Raise vehicle on lift or jack stands at all four corners to provide adequate working clearance underneath.
8. Remove front skid plate if equipped (four mounting bolts).
9. Label and organize all removed fasteners by system (cooling, fuel, electrical, exhaust) to simplify reassembly.

Procedure

1. 1

   Remove air intake system and accessories
   Remove air intake tube from throttle body to air filter housing. Remove air filter housing assembly complete with resonator box. Disconnect mass airflow sensor electrical connector before removal. Remove engine cover by pulling upward on front edge to release grommets.
2. 2

   Disconnect cooling system components
   Remove upper and lower radiator hoses from engine using hose clamp pliers. Disconnect heater hoses at firewall connections. Remove radiator fan shroud assembly (four bolts) and set aside. Disconnect coolant overflow hose from radiator. Remove radiator complete with A/C condenser as single assembly by removing mounting brackets.
3. 3

   Disconnect electrical harnesses and sensors
   Disconnect all engine harness connectors including: alternator, A/C compressor, all ignition coils (6 total), throttle body, fuel injector harness, oxygen sensors (4 total), knock sensors, oil pressure sensor, coolant temperature sensors, and camshaft/crankshaft position sensors. Disconnect main engine harness connector at passenger side firewall. Secure engine harness to engine to prevent snagging during removal.
   ⚠Photograph each connector location before removal. Many connectors appear identical but are circuit-specific.
   Torque spec

   Electrical Connector Bolts8 Nm (6 lb-ft)

   Sensor Bolts12 Nm (9 lb-ft)
4. 4

   Disconnect fuel system
   Disconnect fuel supply line at fuel rail using appropriate fuel line disconnect tool. Cap or plug fuel line to prevent contamination. Verify fuel pressure was properly relieved before disconnecting (no fuel spray should occur). Disconnect EVAP purge line and canister vent lines from intake manifold.
   ⚠️Have fire extinguisher accessible. Work in well-ventilated area away from ignition sources.
5. 5

   Remove serpentine belt and accessory components
   Use serpentine belt tool to rotate tensioner clockwise and remove belt. Remove A/C compressor mounting bolts and secure compressor to frame with wire without disconnecting refrigerant lines. Remove power steering pump mounting bolts and secure pump aside without disconnecting pressure lines. Remove alternator mounting bolts and set aside.
   Torque spec

   Mounting Bolts54 Nm (40 lb-ft)
6. 6

   Disconnect exhaust system
   From underneath vehicle, spray exhaust manifold flange bolts with penetrating oil. Remove exhaust pipe-to-manifold nuts/bolts at both exhaust manifolds (three bolts per side). Support exhaust pipes and lower away from engine. Remove oxygen sensor connectors if not already disconnected.
   ⚠Exhaust fasteners are prone to corrosion. Apply heat if necessary and expect broken studs requiring extraction.
7. 7

   Disconnect transmission connections
   From underneath, disconnect transmission cooler lines at transmission (if automatic). Remove transmission dipstick tube bolt at engine (if equipped). Disconnect any remaining electrical connectors to transmission. Support transmission with transmission jack positioned under transmission pan. Remove transmission inspection cover to access torque converter bolts if automatic transmission.
   ℹ️Transmission must remain supported throughout engine removal process. Adjust jack height as needed.
8. 8

   Separate transmission from engine
   Remove all transmission bellhousing-to-engine block bolts (typically 6-8 bolts around perimeter). For automatic transmission, rotate crankshaft to access and remove all torque converter-to-flexplate bolts (typically 4 bolts) through inspection cover opening. Mark flexplate and torque converter orientation. Carefully pull transmission rearward on transmission jack approximately 2 inches to clear input shaft from clutch or torque converter from crankshaft. Verify transmission is fully supported and stable.
   ⚠Do not allow transmission to hang on input shaft as this can damage transmission front pump or clutch assembly.
9. 9

   Disconnect engine mounts and final connections
   Remove engine mount-to-frame bracket bolts on both driver and passenger sides. Verify throttle cables, cruise control cables, vacuum lines, and all remaining connections are disconnected. Double-check that power steering and A/C lines have adequate slack and will not bind during engine lift.
   ⚠Perform final walk-around inspection to verify all connections, hoses, and wiring are clear before lifting engine.
   Torque spec

   Mounting Bolts54 Nm (40 lb-ft)
10. 10

    Install lifting equipment and remove engine
    Attach engine hoist chains or straps to factory lifting brackets on engine (one at front near thermostat housing, one at rear of cylinder heads). Use load leveler to balance engine angle. Take up slack in hoist and slightly lift engine to verify balance and connection security. Slowly raise engine while monitoring clearance with firewall, A/C lines, power steering lines, and frame rails. Adjust engine angle with load leveler as needed. Once engine is clear of frame rails (approximately 12 inches lift), carefully move hoist forward to fully extract engine from engine bay. Lower engine onto engine stand and secure with stand mounting bolts to engine block.
    ⚠️Never work under suspended engine. Ensure hoist is on stable surface and chains/straps are secure before lifting.
    ⚠Engine will tilt during removal. Front of engine typically rises first. Monitor all clearances continuously during lift.

Reassembly

1. Installation is reverse of removal with the following critical notes:
2. Clean all gasket mating surfaces thoroughly with wire brush and brake cleaner, especially exhaust manifold surfaces and transmission bellhousing face. Any debris will cause leaks.
3. Install new exhaust manifold gaskets and intake manifold gaskets. Do not reuse old gaskets.
4. When mating engine to transmission, ensure torque converter is fully seated in transmission pump (automatic) or input shaft engages clutch splines smoothly (manual). Torque converter should spin freely by hand when properly seated.
5. For automatic transmission, align torque converter to flexplate using marks made during disassembly. Apply thread locker to torque converter bolts per factory specification.
6. Torque all fasteners to specifications using torque wrench. Follow torque sequence for critical components (bellhousing bolts should be tightened in star pattern).
7. Reconnect all electrical connectors to exact original locations using photographs taken during disassembly. Ensure all connector locks click into place.
8. When reinstalling serpentine belt, verify proper routing matches underhood belt routing diagram.
9. Install new oil filter and fill engine with 6.5 quarts Mopar 5W-20 synthetic blend oil.
10. Refill cooling system with Mopar OAT Purple coolant. Burp cooling system by running engine with radiator cap off until thermostat opens and coolant level stabilizes.
11. Torque engine mount bolts to 54.0 Nm (40 lb-ft). Torque gasket surface bolts (intake manifold, exhaust manifolds) to 23.0 Nm (17 lb-ft).
12. Double-check that all hose clamps are tight, all sensors are connected, and no tools or rags remain in engine bay.

Verification

• With engine installed and all connections made, verify oil level on dipstick reads full. Check coolant level in overflow reservoir.
• Before starting engine, turn ignition to ON position (do not start) and verify no warning lights indicate disconnected sensors. Check for fuel leaks at fuel rail connection.
• Reconnect battery cables (positive first, then negative). Clear any diagnostic trouble codes stored during R&R process using scan tool.
• Start engine and verify oil pressure rises within 2-3 seconds. Allow engine to idle and monitor for any fluid leaks (coolant, oil, fuel, power steering).
• Once engine reaches operating temperature (thermostat opens), verify radiator fans cycle on and off properly. Check coolant level and top off as needed after burping system.
• Check for exhaust leaks at manifold connections by listening for ticking or hissing sounds. Verify no vacuum leaks by listening for hissing at intake manifold.
• Test drive vehicle to verify proper transmission engagement, no abnormal noises, normal operating temperature, and all accessories (A/C, power steering, alternator charging) function correctly.
• After test drive, re-inspect all connections for leaks with engine at operating temperature. Re-torque critical fasteners after engine heat cycle if specified by manufacturer.
• Monitor oil and coolant levels over next 100 miles and top off as needed during break-in period.

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