Head Gaskets - Both

Complete replacement of both cylinder head gaskets on the 8.4L V10 engine, including disassembly of intake manifold, exhaust manifolds, valve covers, and cylinder heads.

Warnings

Tools required

Parts

• Cylinder head gasket - left bank × 1 — Use OEM specification
• Cylinder head gasket - right bank × 1 — Use OEM specification
• Cylinder head bolt set (TTY bolts) × 1 — Use OEM specification
• Intake manifold gasket set × 1 — Use OEM specification
• Exhaust manifold gaskets × 2 — Use OEM specification
• Valve cover gaskets with grommets × 2 — Use OEM specification
• Spark plugs × 10 — Use OEM specification
• Coolant temperature sensor O-ring × 1 — Use OEM specification
• Thermostat housing gasket × 1 — Use OEM specification
• Water outlet gaskets × 2 — Use OEM specification

Fluids

• Mopar HOAT coolant 50/50 — 19 qt
• 0W-40 full synthetic engine oil — 11 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery cable and isolate terminal
3. Remove engine cover by pulling upward on front edge to release clips
4. Allow engine to cool completely (minimum 4 hours)
5. Place drain pans under vehicle and drain engine coolant from radiator petcock and engine block drain plugs
6. Drain engine oil and replace oil filter
7. Document all hose routing, electrical connector positions, and bracket locations with photos
8. Relieve fuel system pressure by removing fuel pump relay and cranking engine until it stalls

Procedure

1. 1

   Remove air intake system and throttle body
   Disconnect mass airflow sensor electrical connector. Loosen clamps at air filter housing and throttle body. Remove air intake tube assembly. Disconnect throttle body electrical connector and coolant hoses. Remove throttle body mounting bolts and set throttle body aside. Cap or plug all open coolant passages.
2. 2

   Remove accessory drive components
   Remove serpentine belt by rotating tensioner clockwise and sliding belt off pulleys. Remove alternator mounting bolts and disconnect electrical connections, then set alternator aside with wiring attached. Remove power steering pump mounting bolts and set pump aside without disconnecting hydraulic lines. Remove A/C compressor mounting bolts and secure compressor to frame without disconnecting refrigerant lines.
3. 3

   Disconnect fuel system and electrical connections
   Disconnect fuel supply and return lines at fuel rail using quick-disconnect tool. Disconnect all fuel injector electrical connectors (mark positions for reassembly). Disconnect ignition coil connectors and remove the 10 individual ignition coils (coil-on-plug) from the cylinder heads. Remove spark plugs from all cylinders using spark plug socket. Disconnect engine coolant temperature sensor, camshaft position sensors, and all other electrical connectors from cylinder heads and intake manifold.
4. 4

   Remove intake manifold assembly
   Disconnect all vacuum lines from intake manifold (mark positions). Remove brake booster vacuum line. Disconnect PCV hoses. Remove fuel rail mounting bolts and lift fuel rail with injectors as assembly, setting aside safely. Remove intake manifold mounting bolts working from outside toward center. Carefully lift intake manifold off engine, noting dowel pin locations. Cover intake ports on cylinder heads with clean shop towels to prevent debris entry.
5. 5

   Remove valve covers
   Disconnect any remaining breather hoses or electrical connections to valve covers. Remove valve cover mounting bolts from both left and right covers. Carefully break seal using plastic pry tool if necessary, taking care not to damage sealing surfaces. Lift valve covers off and inspect valve train components for wear or damage. Place clean shop towels over exposed valve train to prevent debris contamination.
6. 6

   Remove exhaust manifolds
   From underneath vehicle, disconnect exhaust pipes from both exhaust manifolds at flange connections. Remove oxygen sensor connectors. Remove exhaust manifold heat shields if equipped. Remove exhaust manifold mounting bolts from both left and right manifolds (working from center outward to prevent warping). Remove exhaust manifolds and set aside. Inspect manifold studs for damage and replace if necessary.
7. 7

   Support engine and remove cylinder head bolts
   Install engine support fixture or position engine hoist to support engine weight safely. Mark cylinder head bolt removal sequence (consult service manual for specific pattern - typically starting from center and working outward in specific sequence). Loosen all cylinder head bolts on first bank in proper sequence, loosening each bolt 1/4 turn at a time in sequence until all are loose. Remove bolts completely and store in order. Repeat process for second bank cylinder head bolts. Note that head bolts should show some stretch and must be replaced with new TTY bolts.
8. 8

   Remove cylinder heads
   Carefully break cylinder head seal using plastic pry points at designated locations (typically at corners or between head and block casting bosses - never pry between sealing surfaces). With assistance, carefully lift first cylinder head straight up off engine block and place on padded work surface with combustion chamber side up. Immediately cover open cylinders on engine block with clean shop towels or plastic to prevent debris entry. Repeat process for second cylinder head. Do not drag heads across block deck surface.
9. 9

   Inspect and clean all sealing surfaces
   Thoroughly inspect cylinder block deck surfaces for flatness using precision straightedge and feeler gauge. Maximum allowable warpage must be verified against the factory service manual specification for the 8.4L V10 (do not rely on a generic value). Use plastic gasket scraper to carefully remove all old gasket material from block deck, cylinder head surfaces, intake manifold surfaces, and exhaust manifold surfaces. Clean all surfaces with degreaser and lint-free cloths. Use compressed air to blow out all coolant passages, oil passages, and bolt holes in block and heads. Vacuum out any remaining debris. Inspect cylinder head surfaces for cracks, especially between valve seats and in combustion chambers. Check cylinder head flatness with straightedge and feeler gauge.
10. 10

    Install new head gaskets and position cylinder heads
    Verify all block deck and head surfaces are completely clean and dry. Install new head gaskets on block deck, ensuring proper orientation (gaskets are marked for left/right and front/back orientation). Align gasket dowel pins with block holes. With assistance, carefully position first cylinder head onto block, aligning with dowel pins and ensuring gasket remains in position. Do not slide head once it contacts gasket. Repeat for second cylinder head. Verify both heads are seated fully on dowels before proceeding.
11. 11

    Install and torque cylinder head bolts
    Install new cylinder head bolts (TTY type) by hand into first cylinder head, ensuring threads engage smoothly. Following the factory-specified tightening sequence, torque the head bolts in the multiple stages defined in the Chrysler service manual for the 8.4L V10 (initial ft-lb stages followed by torque-angle stages using a torque angle gauge). Do not use generic values — obtain the exact sequence and specifications from factory service data. Complete all stages for first head before moving to second head. Repeat entire bolt installation and torquing procedure for second cylinder head using new bolts.
12. 12

    Install exhaust manifolds
    Install new exhaust manifold gaskets on cylinder head exhaust ports. Position exhaust manifolds and install mounting bolts finger-tight, working from center outward. Torque manifold bolts to specification in proper sequence. Install heat shields if equipped. Connect exhaust pipes to manifolds with new gaskets and hardware. Reconnect oxygen sensor connectors.
13. 13

    Install valve covers and intake manifold
    Install new valve cover gaskets with grommets in valve covers. Position valve covers on heads and install mounting bolts, torquing to specification in proper sequence (typically cross-pattern). Remove shop towels from intake ports. Install new intake manifold gaskets on cylinder heads. Position intake manifold carefully onto heads, aligning with dowel pins. Install intake manifold bolts and torque to specification in proper sequence (typically from center outward). Reinstall fuel rail and injector assembly. Reconnect all electrical connectors to injectors, using photos for reference.
14. 14

    Reinstall ignition system and remaining components
    Install new spark plugs and torque to the factory specification for the 8.4L V10 (verify exact value against service data — over-torquing risks damaging the aluminum head threads). Install ignition coil packs into spark plug tubes and secure with mounting bolts. Reconnect all coil pack electrical connectors. Reconnect all engine sensors including coolant temperature sensor (with new O-ring), camshaft position sensors, and any other disconnected sensors. Install throttle body with new gasket and reconnect coolant hoses and electrical connector. Install air intake system and reconnect mass airflow sensor.
15. 15

    Reinstall accessory drive components and perform final assembly
    Reinstall A/C compressor and torque mounting bolts to specification. Reinstall power steering pump and torque mounting bolts to specification. Reinstall alternator and reconnect electrical connections. Install serpentine belt following proper routing diagram. Reconnect all vacuum lines, PCV hoses, and fuel lines using photos for reference. Double-check all electrical connections are secure. Install engine cover.
16. 16

    Refill fluids and prepare for startup
    Refill engine with the factory-specified quantity and grade of engine oil for the 8.4L V10 (verify capacity, approximately 10 quarts with filter, and correct viscosity per the owner's manual). Close radiator petcock and engine block drains. Refill cooling system with the factory-specified capacity of Mopar HOAT 50/50 coolant mixture (verify total system capacity against the service manual). With radiator cap off, turn ignition to ON position (without starting) to prime fuel system. Reconnect negative battery cable. Perform thorough visual inspection of all work areas for forgotten fasteners, tools, or disconnected components.

Reassembly

1. All reassembly steps are included in the main procedure steps
2. Ensure all torque specifications are followed precisely during reassembly
3. Replace all gaskets, seals, and TTY bolts with new parts
4. Follow proper torque sequences for all critical components
5. Use threadlocker where specified by manufacturer

Verification

• Start engine and monitor for unusual noises or vibrations during initial startup
• Check for coolant leaks at head gasket areas, intake manifold, and thermostat housing while engine warms up
• Check for oil leaks at valve covers and other disturbed areas
• Check for exhaust leaks at manifold flanges
• Monitor engine temperature gauge for proper operation and normal operating temperature
• Allow engine to reach full operating temperature, then shut off and recheck coolant level when cool
• Check engine oil level after initial run and top off if necessary
• Perform test drive and monitor for proper engine performance, smooth idle, and normal power delivery
• Recheck all fluid levels after test drive
• Scan for diagnostic trouble codes to ensure all sensors are functioning properly

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