Long Block Replacement

Complete removal and replacement of the long block assembly on a 2014-2018 Chevrolet Silverado 1500 with 5.3L V8 EcoTec3 L83 engine, including engine removal, installation of replacement long block, and reinstallation of all external components.

Warnings

Tools required

Parts

• Long block assembly (5.3L L83 EcoTec3) × 1 — GM 12691783 or remanufactured equivalent
• Engine oil filter × 1 — AC Delco PF63E
• Engine oil drain plug crush washer × 1 — Use OEM specification
• Valve cover gaskets (left and right) × 2 — GM 12642603
• Intake manifold gasket set × 1 — Fel-Pro MS 96053
• Exhaust manifold gaskets (left and right) × 2 — Fel-Pro MS 97376
• Timing cover gasket × 1 — GM 12639263
• Oil pan gasket × 1 — Fel-Pro OS 34548 R
• Water pump gasket × 1 — Use OEM specification
• Thermostat housing gasket × 1 — Use OEM specification
• Exhaust manifold stud/nut set × 1 — Dorman 03412
• Engine coolant (DEX-COOL) × 1 — ACDelco 10-5027
• Engine oil (dexos1 0W-20) × 1 — ACDelco dexos1
• Spark plugs (8 required) × 8 — AC Delco 41-162
• Anti-seize compound × 1 — Permatex 81343
• RTV silicone sealant (black) × 1 — Permatex 81730
• Thread locker (medium strength) × 1 — Loctite 242

Fluids

• ACDelco dexos1 0W-20 — 8.5 qt
• ACDelco DEX-COOL (Orange) — 18 qt

Preparation

1. Park vehicle on level surface and engage parking brake. Chock rear wheels securely.
2. Disconnect negative battery cable, then positive cable. Remove battery from vehicle.
3. Remove engine cover (decorative plastic cover) by pulling upward on retention clips.
4. Drain engine coolant into appropriate container by opening radiator petcock and removing lower radiator hose.
5. Drain engine oil completely and remove oil filter.
6. Relieve fuel system pressure: Remove fuel pump fuse, start engine and allow to stall, then crank for 5 seconds to ensure pressure relief.
7. Raise vehicle on lift to comfortable working height with full undercarriage access.
8. Remove front skid plate if equipped.
9. Label all electrical connectors, vacuum lines, and hose positions with tape and marker or take detailed photographs from multiple angles.
10. If AC system requires disconnection, have system evacuated by certified technician. If AC compressor can remain attached to engine during removal, bracket may be left in place.
11. Position engine hoist and load leveler near vehicle for easy access.
12. Have complete gasket set, fluids, and new fasteners organized and ready.

Procedure

1. 1

   Remove intake and fuel system components
   Remove air intake tube and air filter housing assembly. Disconnect throttle body electrical connector and remove throttle body if desired. Disconnect fuel feed line at fuel rail using appropriate disconnect tool. Cap open fuel lines to prevent contamination. Remove fuel rail with injectors as an assembly (leave injectors attached to rail). Disconnect and label all injector electrical connectors. Remove intake manifold by removing all mounting bolts in reverse of tightening sequence and carefully lifting assembly away. Remove and discard intake manifold gaskets.
   Torque spec

   Intake Manifold Bolts25 Nm (18 lb-ft)
2. 2

   Disconnect engine electrical and sensor connections
   Disconnect all engine electrical connectors including: alternator connections, engine harness-to-chassis harness connectors (typically 3-4 main connectors at firewall), coolant temperature sensors, oil pressure sensor, knock sensors, camshaft position sensors, crankshaft position sensor, oxygen sensors (all 4), MAP sensor, and any remaining sensors. Disconnect ignition coil connectors and remove all 8 ignition coils. Remove spark plugs. Unbolt engine harness from engine at all retention points and position harness aside, routing it away from engine for removal.
   Torque spec

   Electrical Connector Bolts8 Nm (6 lb-ft)

   Sensor Bolts14 Nm (10 lb-ft)
3. 3

   Remove exhaust system components
   Working from underneath vehicle, disconnect all oxygen sensor electrical connectors if not already done. Remove exhaust Y-pipe at catalytic converter flanges. Remove exhaust manifold heat shields. Remove exhaust manifold mounting nuts working from hot (center) to cold (outer) positions. Remove both exhaust manifolds and discard gaskets. Inspect manifold studs for damage; replace any broken or damaged studs.
   ⚠Exhaust manifold studs are prone to breakage on this engine. Apply penetrating oil 24 hours before removal if possible. Have stud extractor set available.
   Torque spec

   Exhaust Manifold Nuts30 Nm (22 lb-ft)
4. 4

   Remove accessory drive components
   Remove serpentine belt by releasing automatic tensioner. Remove alternator mounting bolts and position alternator aside (can remain connected electrically if wires reach). Remove power steering pump mounting bolts and position pump aside with hoses attached if possible. If AC compressor must be removed, disconnect lines (system must be evacuated first) and remove compressor mounting bolts. Otherwise, remove compressor mounting bracket bolts to leave compressor attached to vehicle frame. Remove drive belt tensioner and idler pulleys.
   Torque spec

   Mounting Bolts60 Nm (44 lb-ft)
5. 5

   Disconnect cooling system and remove radiator
   Remove upper radiator hose and lower radiator hose at engine connections. Disconnect transmission cooler lines at radiator (if automatic transmission). Remove radiator support brackets and cooling fan assembly. Remove radiator from vehicle. Disconnect heater hoses at engine (inlet and outlet at rear of engine). Remove thermostat housing if desired for transfer to new engine. Cap all open coolant passages.
6. 6

   Remove valve covers and front accessories
   Remove valve cover bolts in reverse sequence and remove both valve covers. Discard valve cover gaskets. Remove water pump mounting bolts and remove water pump (discard gasket). Remove crankshaft balancer bolt using appropriate holding tool and remove balancer with harmonic balancer puller. Remove timing cover bolts in reverse sequence and remove timing cover. Mark timing chain and sprocket alignment for reference even though new engine will have timing set.
   ⚠Do not use jaw-type puller on harmonic balancer. Use proper balancer puller that bolts to balancer to prevent damage.
   Torque spec

   Cover Bolts20 Nm (15 lb-ft)
7. 7

   Separate transmission from engine
   Support transmission securely with transmission jack. Remove transmission-to-engine mounting bolts (typically 6-8 bolts around bellhousing perimeter). On automatic transmission, ensure torque converter is secured to transmission with safety wire or retaining strap to prevent falling during separation. Carefully separate transmission from engine by pulling straight back, ensuring torque converter remains with transmission. Lower transmission slightly and secure on transmission jack.
   ⚠️Transmission weighs 200+ lbs. Ensure transmission jack is properly positioned and rated for weight. Crushing hazard if transmission falls.
   Torque spec

   Transmission-to-Engine Bolts55 Nm (41 lb-ft)
8. 8

   Remove engine mounts and prepare for extraction
   Attach engine hoist with load leveler to engine lift brackets (factory brackets on cylinder heads or intake manifold mounting points). Apply slight tension to hoist to support engine weight. Remove engine mount-to-frame bolts on both sides. Remove engine mount-to-engine bracket bolts if necessary. Verify all electrical connections, hoses, lines, and cables are disconnected from engine. Perform final inspection around entire engine perimeter for any remaining attachments.
   ⚠️Before lifting engine, verify all connections are disconnected. Engine still connected to vehicle during hoist operation can cause severe damage and injury.
   Torque spec

   Mounting Bolts60 Nm (44 lb-ft)
9. 9

   Extract engine from vehicle
   Slowly raise engine with hoist while using load leveler to maintain proper angle. Engine will need to tilt slightly nose-up to clear transmission bellhousing area and front crossmember. Carefully guide engine forward and upward, watching clearances at firewall, frame rails, and AC lines. Once engine is clear of engine bay, move hoist away from vehicle. Lower engine onto engine stand if available, or secure on heavy-duty stand with appropriate blocking.
10. 10

    Transfer external components to new long block
    Working systematically, transfer all external components from old engine to new long block: oil pan (clean and install with new gasket), timing cover and timing components if not included with long block (install with new gasket), water pump (new gasket), thermostat and housing (new gasket), valve covers (new gaskets), exhaust manifolds (new gaskets and apply anti-seize to studs), fuel rails and injectors, all sensors (coolant temp, oil pressure, knock sensors, cam/crank position sensors), engine harness brackets, alternator bracket, AC compressor bracket, power steering pump bracket, and any other components specific to your configuration. Install new spark plugs. Follow all applicable torque specifications and sequences.
    ℹ️Apply thin bead of RTV silicone at timing cover-to-oil pan junction and oil pan corners before installing gaskets. Allow RTV to set for 10 minutes before final installation.
    Torque spec

    Oil Pan Bolts12 Nm (9 lb-ft)

    Cover Bolts20 Nm (15 lb-ft)

    Exhaust Manifold Nuts30 Nm (22 lb-ft)

    Mounting Bolts60 Nm (44 lb-ft)

    Gasket Bolts25 Nm (19 lb-ft)

    Gasket Surface Bolts26 Nm (19 lb-ft)
11. 11

    Install prepared long block into vehicle
    Attach engine hoist to new long block using lift brackets. Raise engine to appropriate height and angle. Carefully guide engine into engine bay, reversing extraction process. Tilt engine to clear front crossmember and align with transmission bellhousing. Watch all clearances carefully during installation. Once engine is positioned in engine bay, align engine with transmission input shaft and bellhousing. Carefully push engine rearward while maintaining alignment, ensuring torque converter alignment on automatic transmission or clutch disk alignment on manual transmission.
    ⚠Do not force engine to mate with transmission. Misalignment can damage transmission input shaft, torque converter, or clutch components. Engine should slide into place with minimal force when properly aligned.
12. 12

    Secure engine and transmission assembly
    Install transmission-to-engine mounting bolts and tighten to specification in a crossing pattern to ensure even seating. Install engine mount brackets to engine if removed, then lower engine onto frame mounts. Install engine mount-to-frame bolts and tighten to specification. Remove engine hoist and load leveler once engine is fully supported by mounts. Remove transmission jack support.
    Torque spec

    Transmission-to-Engine Bolts55 Nm (41 lb-ft)

    Mounting Bolts60 Nm (44 lb-ft)
13. 13

    Reinstall accessory drive components and front accessories
    Install harmonic balancer onto crankshaft, ensuring proper seating. Install crankshaft bolt to specification (requires holding tool to prevent rotation). Install drive belt tensioner and idler pulleys with mounting bolts. Install AC compressor or reconnect compressor bracket. Install power steering pump with mounting bolts. Install alternator with mounting bolts. Reconnect all accessory electrical connections.
    Torque spec

    Mounting Bolts60 Nm (44 lb-ft)
14. 14

    Reconnect cooling system and install radiator
    Install radiator into vehicle with support brackets. Reconnect transmission cooler lines if equipped. Install cooling fan assembly. Install upper and lower radiator hoses at engine. Install heater hoses at rear of engine (inlet and outlet). Ensure all hose clamps are properly positioned and tightened.
15. 15

    Reconnect fuel system, intake, and all electrical connections
    Install intake manifold with new gaskets, torquing bolts in proper sequence from center outward. Install fuel rail assembly with injectors and connect all injector electrical connectors. Connect fuel feed line at fuel rail. Install throttle body if removed. Reconnect all engine sensors and electrical connections using labels and photos from disassembly: cam/crank position sensors, knock sensors, oil pressure sensor, coolant temp sensors, alternator, oxygen sensors (all 4), MAP sensor, and engine harness-to-chassis connectors. Install ignition coils and connect coil electrical connectors. Install air filter housing and intake tube.
    Torque spec

    Intake Manifold Bolts25 Nm (18 lb-ft)

    Electrical Connector Bolts8 Nm (6 lb-ft)

    Mounting Bolts60 Nm (44 lb-ft)
16. 16

    Install exhaust system and complete underbody work
    Install exhaust manifolds with new gaskets, applying anti-seize to studs and torquing nuts from hot (center) to cold (outer). Install exhaust manifold heat shields. Install Y-pipe to exhaust manifold flanges and tighten all fasteners. Reconnect oxygen sensor connectors if not already done. Install front skid plate if equipped. Install engine oil drain plug with new crush washer and torque to specification. Install new oil filter.
    Torque spec

    Exhaust Manifold Nuts30 Nm (22 lb-ft)

    Oil Drain Plug35 Nm (26 lb-ft)
17. 17

    Fill fluids and perform initial checks
    Fill engine with 8.5 quarts of ACDelco dexos1 0W-20 engine oil. Fill cooling system with 50/50 mixture of ACDelco DEX-COOL coolant and distilled water (approximately 18 quarts total system capacity). Install radiator cap. Reinstall battery and connect positive cable, then negative cable. Install engine cover. Perform visual inspection of all connections, ensuring no tools or parts are left in engine bay. Check that all fasteners are tight and all electrical connectors are fully seated.

Reassembly

1. Double-check all torque specifications were followed, especially torque-to-yield fasteners that require angle tightening after initial torque
2. Verify serpentine belt is properly routed according to belt routing diagram on fan shroud
3. Ensure all electrical grounds are properly connected and bolted to engine block and frame
4. If AC system was opened, have system evacuated, pressure tested, and recharged by certified technician
5. Verify transmission fluid level is correct after engine installation (check with engine running, transmission in park, at operating temperature)

Verification

• Prime oil system by cranking engine with fuel pump fuse removed and ignition coils disconnected until oil pressure gauge shows pressure (typically 5-10 seconds of cranking)
• Reinstall fuel pump fuse and reconnect ignition coils. Start engine and verify it starts and runs smoothly
• Check for any oil, coolant, or fuel leaks around all gasket surfaces, connections, and fittings while engine is running
• Verify oil pressure is within normal range on gauge (should show 40-70 PSI at idle when warm)
• Allow engine to reach operating temperature and verify cooling fans cycle properly and temperature remains stable
• Check coolant level after engine reaches operating temperature and add as necessary (system may need burping to remove air pockets)
• Verify all gauges and warning lights function properly and show normal readings
• Scan for diagnostic trouble codes using OBD-II scanner. Address any codes that appear
• Perform test drive to verify proper engine performance, transmission shifting, and absence of unusual noises or vibrations
• Recheck all fluid levels after test drive and inspect for any new leaks
• Perform idle relearn procedure if required (may need to use scan tool or follow specific idle procedure for this engine)
• After 500 miles, recheck valve cover bolts, intake manifold bolts, and exhaust manifold nuts for proper torque as initial heat cycling can cause settling

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle