Head Gasket - Single

Complete procedure for replacing a single cylinder head gasket on the 2008 Dodge Viper 8.4L V10 engine, including removal of intake manifold, exhaust manifolds, and associated components.

Warnings

Tools required

Parts

• Cylinder head gasket × 1 — Use OEM Mopar specification
• Cylinder head bolts (TTY) × 1 — Use OEM Mopar - MUST be new
• Intake manifold gaskets × 1 — Use OEM specification
• Exhaust manifold gaskets × 1 — Use OEM specification
• Valve cover gasket × 1 — Use OEM specification
• Coolant temperature sensor O-ring × 1 — Replace if disturbed
• Spark plugs × 5 — Replace while accessible
• Anti-seize compound × 1 — For exhaust fasteners

Fluids

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

Preparation

1. Ensure vehicle is on level ground with parking brake engaged and transmission in Park (or 1st gear for manual).
2. Disconnect negative battery cable and secure away from battery post.
3. Remove engine cover panels and any decorative covers.
4. Drain engine coolant completely into appropriate container by opening radiator petcock and removing lower radiator hose.
5. Drain engine oil and remove oil filter.
6. Relieve fuel system pressure by removing fuel pump fuse and cranking engine until it stalls.
7. Label and photograph all electrical connectors, vacuum lines, and hose routing for reference during reassembly.
8. Support engine weight using engine hoist or support fixture attached to lifting eyes on engine.

Procedure

1. 1

   Remove air intake system
   Remove air intake tube, air filter housing, and mass airflow sensor assembly. Disconnect all associated vacuum lines and electrical connectors. Remove throttle body connections and any supporting brackets. Set components aside in clean area.
2. 2

   Remove accessory drive components
   Remove serpentine belt by releasing tensioner. Remove alternator with mounting brackets. Disconnect power steering pump and secure aside without disconnecting hoses (if interfering with access to target head). Remove A/C compressor mounting bolts and secure aside without disconnecting refrigerant lines. Note exact routing of all brackets for reassembly.
3. 3

   Disconnect fuel and coolant systems
   After relieving fuel system pressure, disconnect the fuel supply line from the fuel rail using the appropriate quick-disconnect tool and cap the line. Cap all open fuel lines to prevent contamination. Remove upper and lower radiator hoses. Disconnect heater hoses from engine. Remove coolant bypass tubes if they obstruct head access. Disconnect all coolant temperature sensor connectors.
4. 4

   Remove intake manifold assembly
   Disconnect all fuel injector electrical connectors. Remove fuel rail mounting bolts and carefully lift fuel rail with injectors attached (set aside safely). Disconnect all vacuum lines from intake manifold including brake booster, PCV, and EVAP connections. Remove throttle body if not already removed. Disconnect intake manifold absolute pressure (MAP) sensor and any other sensors. Remove intake manifold bolts in reverse of tightening sequence (outside to inside pattern). Carefully lift intake manifold from engine, using plastic pry points if necessary. Do not pry against gasket surfaces.
   Torque spec

   Intake Manifold Bolts25 Nm (18 lb-ft)
5. 5

   Remove valve cover
   Disconnect the individual coil-on-plug ignition coil connectors and remove the ignition coils to gain access. Then remove valve cover fasteners. Remove valve cover fasteners evenly, then lift the cover. Gently tap valve cover with rubber mallet if stuck, then lift off. Remove and discard valve cover gasket. Inspect valve train for obvious damage or excessive wear.
6. 6

   Remove exhaust manifold
   Spray exhaust manifold fasteners with penetrating oil and allow to soak. Disconnect oxygen sensors from exhaust manifold. Support exhaust system with jack or hanger to prevent strain on remaining connections. Remove exhaust manifold heat shields. Remove exhaust manifold nuts working from center outward to prevent warping. Separate exhaust manifold from cylinder head and remove gasket. Inspect manifold for cracks or warping.
   Torque spec

   Exhaust Manifold Nuts25 Nm (18 lb-ft)
7. 7

   Remove rocker arms and pushrods
   Note the orientation and position of each rocker arm for reinstallation in exact same location. Loosen rocker arm bolts and remove rocker arms, keeping them organized by cylinder position. Remove pushrods one at a time, keeping them in order. Stand pushrods vertically in a holder or use numbered slots to maintain position. Inspect pushrods for straightness by rolling on flat surface - any bent pushrods must be replaced. Inspect rocker arm contact surfaces for wear or scoring.
8. 8

   Disconnect remaining head attachments
   Remove spark plugs from all cylinders on the head being serviced. Disconnect any remaining ground straps, coolant temperature sensors, or bracket attachments to the cylinder head. Verify no hoses, wires, or brackets remain connected that would prevent head removal.
9. 9

   Remove cylinder head bolts
   Using a breaker bar and socket, loosen cylinder head bolts in reverse of tightening sequence (work from outside bolts toward center in a crisscross pattern). Remove all cylinder head bolts completely. These are torque-to-yield bolts and must be discarded - do not reuse. Inspect bolt holes in block for coolant or oil contamination, clean if necessary.
10. 10

    Remove cylinder head
    Carefully break cylinder head free from block using plastic pry points at designated pry locations (typically at corners where casting is reinforced). Never pry between gasket surfaces. Once free, lift cylinder head straight up to avoid damaging deck surface or interfering with other components. The head is extremely heavy - use assistance or lifting equipment. Place cylinder head on padded surface with combustion chambers facing up.
11. 11

    Clean and inspect surfaces
    Remove all gasket material from cylinder head and engine block deck surfaces using plastic gasket scraper first, then carefully with metal scraper if needed. Do not gouge or scratch sealing surfaces. Clean surfaces thoroughly with brake cleaner and lint-free cloths. Use shop vacuum to remove all debris from cylinder bores and coolant passages. Inspect cylinder head deck surface for warping using precision straight edge and feeler gauge - maximum allowable warpage is typically 0.003 inches. Check block deck surface similarly. Inspect cylinder bores for scoring or damage. If warpage exceeds specification or surfaces are damaged, cylinder head must be machined or replaced.
12. 12

    Prepare for reassembly
    Chase all cylinder head bolt holes in block with appropriate thread chaser to remove any residue or corrosion. Blow out bolt holes with compressed air. Verify bolt holes are dry - any oil or coolant in holes will cause false torque readings and potential head gasket failure. Install new cylinder head gasket on block deck, ensuring it is oriented correctly (markings typically indicate TOP and FRONT). Align gasket dowel pins. Do not use any sealant on multi-layer steel head gaskets unless specifically required by manufacturer.
13. 13

    Install cylinder head
    Carefully lower cylinder head onto block, aligning head with dowel pins and head gasket. Ensure head seats completely on gasket without shifting gasket position. Hand-start all new cylinder head bolts (TTY bolts) to ensure threads are not crossed. Do not apply any lubricant to bolt threads unless specifically instructed by manufacturer.
14. 14

    Torque cylinder head bolts
    Following the proper tightening sequence (typically from center outward in a spiral pattern - refer to service manual diagram), perform the four-step torque procedure: Step 1 - Torque all bolts to 40 Nm (30 lb-ft). Step 2 - Torque all bolts to 80 Nm (59 lb-ft) following same sequence. Step 3 - Rotate all bolts an additional 90 degrees in sequence using angle gauge. Step 4 - Rotate all bolts another 90 degrees in sequence (total 180 degrees additional rotation after Step 2). Verify each bolt rotates smoothly during angle tightening - any binding indicates problem. Mark bolts with paint pen after each step to track progress.
    Torque spec

    Cylinder Head Bolts - Step 140 Nm (30 lb-ft)

    Cylinder Head Bolts - Step 280 Nm (59 lb-ft)

    Cylinder Head Bolts - Step 30 Nm (0 lb-ft) + 90°

    Cylinder Head Bolts - Step 40 Nm (0 lb-ft) + 90°
15. 15

    Install pushrods and rocker arms
    Apply engine assembly lubricant to pushrod ends and rocker arm contact points. Install pushrods in their exact original locations, ensuring each seats properly in lifter cup (rotate pushrod while pushing down to verify seating). Install rocker arms in original positions with rocker arm bolts. Rotate engine to position each cylinder at base circle (lifter not on cam lobe) before tightening that cylinder's rocker arm bolts. Tighten rocker arm bolts to specification (typically 25-30 Nm but verify in service manual). Verify proper valve train geometry and lash after installation.
16. 16

    Install exhaust manifold
    Install new exhaust manifold gasket on cylinder head. Apply high-temperature anti-seize compound to exhaust manifold stud threads only if specified by the service manual, and adjust torque accordingly. Otherwise install fasteners clean. Position exhaust manifold and start all nuts by hand. Torque exhaust manifold nuts to 25 Nm (18 lb-ft) in a crisscross pattern from center outward. Reconnect oxygen sensors, applying anti-seize to sensor threads. Install heat shields.
    Torque spec

    Exhaust Manifold Nuts25 Nm (18 lb-ft)
17. 17

    Install valve cover and intake manifold
    Install new valve cover gasket (use small dabs of RTV sealant at corners if specified by manufacturer). Install valve cover and torque bolts in crisscross pattern to specification (typically 10-12 Nm). Position new intake manifold gaskets on cylinder heads. Lower intake manifold into place, ensuring gaskets remain properly positioned. Install intake manifold bolts and torque to 25 Nm (18 lb-ft) following proper sequence (center outward). Reinstall fuel rail with injectors, torquing rail bolts to specification.
    Torque spec

    Intake Manifold Bolts25 Nm (18 lb-ft)
18. 18

    Reinstall ignition and fuel systems
    Install new spark plugs, applying anti-seize only if specified by the plug/engine manufacturer, and torque to specification. Reinstall ignition coils and reconnect coil connectors. Reconnect fuel lines to fuel rail using new O-rings if required. Reconnect all fuel injector electrical connectors.
19. 19

    Reinstall accessories and cooling system
    Reinstall all brackets, sensors, and ground straps to cylinder head in reverse order of removal. Reconnect coolant temperature sensors. Install coolant bypass tubes with new O-rings. Reconnect heater hoses and radiator hoses with new clamps. Reinstall power steering pump, A/C compressor, and alternator with all mounting brackets. Install serpentine belt following correct routing diagram. Reinstall air intake system components.
20. 20

    Fill fluids and initial startup
    Install new oil filter and fill engine with the specified quantity of 0W-40 full synthetic oil (verify exact capacity in service manual, approximately 10 quarts). Fill cooling system with 50/50 mix of Mopar HOAT coolant (verify exact system capacity in service manual - may require multiple fill/burp cycles). Leave radiator cap off initially. Reconnect battery negative cable. Turn ignition to ON position (do not start) to prime fuel system - repeat 3 times. Remove any air pockets from cooling system by running engine briefly and adding coolant as needed. Start engine and check immediately for any coolant, oil, or fuel leaks. Allow engine to reach operating temperature while monitoring for leaks and unusual noises. Check coolant level again after engine reaches temperature and add as necessary. Shut down and recheck all connections after engine cools.

Reassembly

1. All fasteners should be reinstalled in reverse order of removal unless specific torque sequences are provided.
2. Always use new cylinder head bolts (TTY type) - never reuse old head bolts.
3. Ensure all electrical connectors are fully seated and locked - verify with gentle pull test.
4. Double-check all vacuum line connections match original routing photographs.
5. Verify serpentine belt is properly seated in all pulley grooves before final tensioning.
6. Check that no tools or shop rags remain in engine compartment before startup.

Verification

• Start engine and verify no coolant leaks from head gasket, intake manifold, or coolant hoses.
• Verify no oil leaks from valve cover or any disturbed connections.
• Check for smooth idle with no unusual valve train noise, ticking, or knocking.
• Verify all cylinders are firing by monitoring engine smoothness and exhaust sound.
• After engine reaches operating temperature, verify cooling fans operate properly and temperature remains stable.
• Perform test drive to verify proper engine performance under load.
• Recheck coolant level after engine has fully cooled from first heat cycle - top off as needed.
• After 500 miles, recheck valve cover and intake manifold bolt torque, and verify no new leaks have developed.

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