Long Block Replacement

Complete removal and replacement of the 8.4L V10 long block assembly, including disassembly of all external components, engine extraction, installation of replacement long block, and reinstallation of all ancillaries.

Warnings

Tools required

Parts

• Long block assembly (8.4L V10) × 1 — Use OEM specification
• Engine oil filter × 1 — Use OEM specification
• Coolant hoses (if damaged) × 1 — Inspect and replace as needed
• Exhaust manifold gaskets × 2 — Use OEM specification
• Intake manifold gaskets × 1 — Use OEM specification
• Engine oil × 11 — 0W-40 full synthetic
• Engine coolant × 19 — Mopar HOAT 50/50
• Various o-rings and seals × 1 — Inspect all connections

Fluids

• engine_oil — 11 qt
• coolant — 19 qt

Preparation

1. Park vehicle on level surface and engage parking brake. Chock rear wheels.
2. Disconnect negative battery cable, then positive battery cable. Remove battery from vehicle.
3. Remove engine cover by releasing quick-connect fasteners.
4. Place drain pan under vehicle and drain engine oil completely. Remove oil filter.
5. Drain coolant from radiator drain plug and engine block drain plugs into appropriate container.
6. Relieve fuel system pressure by removing fuel pump fuse and running engine until it stalls, then crank for 5 seconds.
7. Raise vehicle on lift or support securely on jack stands at all four corners.
8. Have A/C system professionally recovered and evacuated.
9. Remove hood by marking hinge positions and disconnecting hood support struts with assistance.

Procedure

1. 1

   Remove intake system and accessories
   Remove air intake assembly from throttle body to air filter housing. Disconnect MAF sensor electrical connector. Remove complete intake tubing. Disconnect throttle body electrical connector and any vacuum lines attached to intake manifold. Remove engine harness cover panels to access wiring.
2. 2

   Disconnect fuel system
   Locate fuel rail and fuel lines at rear of engine. Use appropriate fuel line disconnect tools to separate supply and return lines. Cap all open fuel lines to prevent contamination. Disconnect fuel injector electrical connectors at each cylinder (label each connector location).
   ⚠️Ensure fuel pressure is fully relieved. Have fire extinguisher nearby and work in well-ventilated area.
3. 3

   Remove serpentine belt and accessories
   Rotate serpentine belt tensioner to release tension and remove belt. Remove power steering pump with lines attached and secure aside without disconnecting lines. Remove alternator after disconnecting electrical connections and mounting bolts. Remove A/C compressor mounting bolts (disconnect refrigerant lines at firewall after system recovery) and secure compressor aside. Remove idler pulleys and belt tensioner as needed for clearance.
4. 4

   Disconnect cooling system components
   Disconnect upper and lower radiator hoses from engine. Disconnect heater hoses at firewall connections. Remove coolant bypass hoses if present. Disconnect radiator fan electrical connectors. If clearance requires, remove radiator assembly by removing radiator mounting bolts. Note: the 2008 Viper is manual transmission only, so no automatic transmission cooler lines are present.
5. 5

   Disconnect exhaust system
   From underneath vehicle, spray exhaust fasteners with penetrating oil. Disconnect exhaust pipes from both exhaust manifold flanges. Remove exhaust hangers as needed to lower exhaust system away from engine. On the 2008 Viper, verify exhaust routing against the factory service manual before disconnecting; separate the exhaust at the manifold flanges and remove hangers as needed to lower the system.
6. 6

   Disconnect engine electrical systems
   Disconnect all remaining engine harness connectors including: crankshaft position sensor, camshaft position sensors, knock sensors, oil pressure sender, coolant temperature sensors, coil-on-plug connectors (individual coil per cylinder, 10 total), and any remaining chassis-to-engine harness connectors. Release harness from engine mounting clips. Disconnect ground straps from engine block to chassis at multiple locations.
7. 7

   Separate transmission from engine
   Support transmission with transmission jack. Remove bellhousing-to-engine block bolts (note bolt lengths and locations as they vary). Since the 2008 Viper is manual-only, disconnect the clutch hydraulic line at the correct point (verify whether the slave cylinder is external or internal/concentric per the factory service manual). Disconnect any transmission electrical connectors and vehicle speed sensors. Carefully separate transmission from engine by sliding straight back to clear input shaft from clutch assembly. Lower transmission slightly and support securely.
8. 8

   Prepare engine for removal
   Attach engine hoist chains or straps to factory lifting points on cylinder heads (one front, one rear on each bank). Use engine leveler to balance load. Verify all electrical connectors, hoses, lines, and mechanical connections are disconnected. Check starter motor has been removed or disconnected as needed.
9. 9

   Remove engine mounts
   Locate engine mount brackets on both sides of engine block. Remove engine mount through-bolts securing mounts to chassis brackets. Remove any remaining bolts securing engine mount brackets to engine block. Slightly lift engine with hoist to separate mounts and verify engine is free from all attachment points.
   ⚠Have assistant guide engine during extraction to prevent component damage. V10 is long and requires careful maneuvering.
10. 10

    Extract engine from vehicle
    Slowly lift engine while adjusting leveler to maintain proper angle for clearance. Tilt engine as needed to clear radiator support, steering components, and chassis rails. Pull engine forward and up simultaneously to clear engine bay. Once clear, lower onto engine stand and secure properly for disassembly of remaining external components.
11. 11

    Transfer components to new long block
    Remove all remaining components from old engine and transfer to replacement long block including: intake manifold, throttle body, fuel rails and injectors, ignition coils, all sensors (coolant temp, oil pressure, knock sensors, crank/cam position), exhaust manifolds, engine mounts and brackets, alternator bracket, A/C compressor bracket, power steering pump bracket, starter motor, oil dipstick tube, coolant bypass fittings, and any other external accessories. Install new exhaust manifold gaskets and intake manifold gaskets with replacement components. Inspect all sensors and replace if condition is questionable.
12. 12

    Prepare new long block for installation
    Verify new long block includes all internal components (crankshaft, pistons, camshaft, etc.) as specified. Install new oil filter. Pre-fill oil filter with fresh oil. Add approximately 8 quarts of 0W-40 full synthetic oil to new engine (will top off after installation; verify total capacity against factory service manual). Prime oil system if dry long block by rotating oil pump or following manufacturer priming procedure. Attach hoist to lifting points on new engine and balance on leveler.
13. 13

    Install engine into vehicle
    Carefully guide engine into engine bay reversing extraction path. Tilt and maneuver as needed to clear all chassis components. Align engine with transmission while lowering into position. Have assistant guide input shaft into clutch disc pilot bearing. Continue lowering engine until engine mounts align with chassis brackets. Install engine mount through-bolts finger-tight but do not fully torque yet.
14. 14

    Reconnect transmission to engine
    Verify transmission is properly supported and aligned with engine. Push transmission forward to fully seat bellhousing against engine block. Install all bellhousing-to-engine bolts in correct locations (note that bolt lengths vary). Torque bellhousing bolts in cross-pattern to ensure proper seating. For manual transmission, reconnect clutch hydraulic line. Reconnect transmission electrical connectors.
15. 15

    Reconnect all systems
    Torque engine mount bolts to specification. Reconnect all engine electrical harness connectors using labels and photographs for reference. Reconnect ground straps. Install exhaust system to manifold flanges with new gaskets. Reconnect coolant hoses (upper radiator, lower radiator, heater hoses, bypass hoses). Reinstall radiator if removed. Install A/C compressor and reconnect refrigerant lines. Install power steering pump. Install alternator and reconnect electrical connections. Install serpentine belt following proper routing. Reconnect fuel supply and return lines. Reconnect throttle body. Install intake system and air filter assembly.
16. 16

    Fill fluids and perform initial checks
    Top off engine oil to proper level on dipstick (verify total capacity against factory service manual, approximately 10-11 quarts of 0W-40 full synthetic). Fill cooling system with Mopar HOAT 50/50 coolant through radiator and overflow tank (verify total system capacity against factory service manual, approximately 19 quarts). Reinstall battery and connect positive then negative cables. Install hood by aligning with marked positions. Before starting, verify all connections are secure, no tools remain in engine bay, and all fluid levels are correct.

Reassembly

1. Reassembly is covered in the installation steps above. Ensure all torque specifications are followed for critical fasteners.
2. Double-check all electrical connector engagements by gently pulling on each connection.
3. Verify serpentine belt routing matches factory diagram before starting engine.
4. After A/C line reconnection, system must be evacuated and recharged by certified technician.

Verification

• Start engine and immediately verify oil pressure gauge shows pressure within 5 seconds. If no pressure, shut down immediately and investigate.
• Allow engine to warm to operating temperature while monitoring for leaks (coolant, oil, fuel).
• Check for proper thermostat operation by monitoring coolant temperature gauge and feeling radiator hoses for flow.
• Verify all warning lights extinguish after startup (check engine, oil pressure, temperature).
• Rev engine to 2000-3000 RPM and verify smooth operation with no unusual noises, vibrations, or exhaust smoke.
• With engine at operating temperature, shut down and recheck all fluid levels, adjusting as necessary.
• Test drive vehicle through all gears and verify proper operation under load.
• After test drive, perform final inspection for leaks and verify torque on all accessible critical fasteners.
• Clear any diagnostic trouble codes and verify no new codes set after engine replacement.
• Have A/C system performance tested after refrigerant recharge to verify proper operation.

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