Complete long block replacement procedure for the 2016-2021 Honda Civic 1.5L turbocharged engine, including removal of engine from vehicle, transfer of external components, and reinstallation.

Warnings

Tools required

Parts

• Long block assembly (1.5L turbo) × 1 — Use OEM specification
• Engine oil filter × 1 — 15400-PLM-A02
• Oil drain plug crush washer × 1 — 94109-14000
• Valve cover gasket × 1 — Use OEM specification
• Timing cover gasket × 1 — Use OEM specification
• Oil pan gasket × 1 — Use OEM specification
• Exhaust manifold gasket × 1 — Use OEM specification
• Intake manifold gasket × 1 — Use OEM specification
• Exhaust downpipe gasket × 1 — Use OEM specification
• Throttle body gasket × 1 — Use OEM specification
• Engine coolant × 1 — Honda Type 2 (Blue)
• Engine oil 0W-20 × 1 — Honda Genuine 0W-20
• Left engine mount × 1 — Use OEM specification if damaged
• Right engine mount × 1 — Use OEM specification if damaged
• Rear engine mount × 1 — Use OEM specification if damaged
• Anti-seize compound × 1 — Nickel-based

Fluids

• Honda Genuine 0W-20 — 4 qt
• Honda Type 2 Coolant (Blue) — 6 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery terminal and wait minimum 3 minutes
3. Remove engine cover and undertray
4. Relieve fuel system pressure by removing fuel pump fuse and running engine until it stalls
5. Drain engine coolant completely from radiator drain and engine block drain
6. Drain engine oil and remove oil filter
7. Raise vehicle on jack stands at proper lift points and support securely
8. Remove front wheels for access to subframe area
9. Remove radiator, intercooler, and cooling fans as assembly
10. Disconnect all electrical connectors from engine and label each connection
11. Tag and photograph all vacuum lines, breather hoses, and fuel lines before removal

Procedure

1. 1

   Remove intake and exhaust systems
   Remove air intake system from turbocharger inlet to air box. Disconnect turbocharger inlet and outlet pipes. Remove exhaust downpipe from turbocharger, supporting pipe to prevent damage. Disconnect all vacuum lines from intake manifold and throttle body. Remove charge air cooler pipes from turbocharger and throttle body.
2. 2

   Disconnect fuel and cooling systems
   Disconnect fuel supply and return lines using proper fuel line disconnect tools. Cap open fuel lines immediately. Disconnect all coolant hoses from engine including upper and lower radiator hoses, heater hoses, and thermostat housing connections. Disconnect EVAP purge line and brake booster vacuum line.
   ⚠Have shop towels ready as residual fuel and coolant will drain from disconnected lines.
3. 3

   Remove accessory drive components
   Remove serpentine belt by releasing tensioner. Remove power steering pump and set aside without disconnecting hydraulic lines. Remove A/C compressor and secure to frame without disconnecting refrigerant lines. Remove alternator and starter motor, disconnecting electrical connections.
4. 4

   Separate transmission from engine
   Support transmission securely with transmission jack. Remove all transmission-to-engine bolts working from top and bottom of vehicle. Carefully separate transmission from engine, ensuring torque converter remains with transmission on automatic models or that clutch assembly stays with flywheel on manual models. Lower transmission slightly and secure safely.
   ⚠️Transmission weighs over 100 lbs. Ensure transmission jack is properly positioned and rated for load.
   Torque spec

   Transmission-to-Engine Bolts55 Nm (41 lb-ft)
5. 5

   Disconnect engine mounts
   Remove right engine mount (timing chain side) by removing through-bolt and mount-to-bracket bolts. Remove left engine mount (exhaust side) similarly. Remove rear engine mount from transmission side. Keep mount hardware organized as some bolts may have different lengths.
   ⚠Ensure engine hoist is supporting full engine weight before removing final mount bolts.
   Torque spec

   Mounting Bolts45 Nm (33 lb-ft)
6. 6

   Remove engine from vehicle
   Attach engine hoist to factory lifting points on engine block. Take up slack in hoist chain and verify secure attachment. Perform final check that all hoses, wires, and mounts are disconnected. Slowly lift engine, using leveler to keep engine approximately level. Angle engine as needed to clear firewall, subframe, and chassis components. Once clear of engine bay, lower engine onto engine stand and secure at block mounting points.
   ⚠️Have assistant guide engine during removal to prevent contact with body panels or chassis. Move slowly and deliberately.
7. 7

   Transfer external components to new long block
   Remove all external components from old engine to transfer to new long block: turbocharger and oil feed/return lines, exhaust manifold with studs, intake manifold, throttle body, fuel rail and injectors, ignition coils, all sensors (cam position, crank position, coolant temp, oil pressure, knock), thermostat housing, water pump if not included with long block, oil pan and pickup tube, timing cover, valve cover, dipstick tube, engine mounts, and flywheel or flexplate. Inspect each component and replace if worn or damaged.
   ℹ️Apply anti-seize to exhaust manifold studs before installing nuts.
   ⚠Inspect turbocharger for shaft play and oil leaks before reinstalling.
   Torque spec

   Exhaust Manifold Nuts30 Nm (22 lb-ft)

   Intake Manifold Bolts25 Nm (18 lb-ft)

   Oil Pan Bolts12 Nm (9 lb-ft)

   Flywheel Bolts95 Nm (70 lb-ft)

   Cover Bolts15 Nm (11 lb-ft)
8. 8

   Install timing components
   Install timing chain, guides, and tensioner if not pre-installed on long block. Verify timing marks align correctly on crankshaft and camshaft sprockets. Install timing chain tensioner with retention pin or clip compressed. Install timing cover with new gasket, ensuring alignment dowels are seated. Tighten timing cover bolts in sequence from center outward.
   ⚠Double-check cam and crank timing marks before installing timing cover. Incorrect timing will cause engine damage.
   Torque spec

   Timing Chain Tensioner Bolt25 Nm (18 lb-ft)

   Cover Bolts15 Nm (11 lb-ft)
9. 9

   Install valve cover and sensors
   Install new valve cover gasket and torque valve cover bolts in sequence from center outward. Install all sensors to specified torque: camshaft position sensor, crankshaft position sensor, coolant temperature sensor, oil pressure sensor, and knock sensor. Route sensor wiring in original locations and secure with clips.
   Torque spec

   Cover Bolts15 Nm (11 lb-ft)

   Sensor Bolts10 Nm (8 lb-ft)
10. 10

    Install engine into vehicle
    Attach engine hoist to lifting points on prepared long block. Carefully lift and maneuver engine into engine bay, reversing removal angle. Align engine with transmission while lowering. Guide engine onto mounts while aligning transmission input shaft with clutch or torque converter pilot. Take time to ensure proper alignment before final positioning.
    ⚠️Do not force engine into position. Misalignment can damage transmission input shaft or clutch assembly.
11. 11

    Install engine mounts and mate transmission
    Install all engine mount bolts and torque to specification. Start with rear mount, then left, then right mount. Ensure mounts are not twisted or bound. Install all transmission-to-engine bolts and torque in star pattern to ensure even clamping force. Remove transmission jack once all bolts are torqued.
    Torque spec

    Mounting Bolts45 Nm (33 lb-ft)

    Transmission-to-Engine Bolts55 Nm (41 lb-ft)
12. 12

    Reconnect accessory components
    Reinstall starter motor and alternator with electrical connections. Install A/C compressor to mounting bracket. Install power steering pump. Install serpentine belt and verify proper tension and routing. Ensure all pulleys rotate freely before proceeding.
13. 13

    Reconnect fuel, cooling, and vacuum systems
    Connect all coolant hoses and secure with clamps. Install thermostat housing if removed. Connect heater hoses. Reconnect fuel supply and return lines, ensuring they click into place. Connect brake booster vacuum line, EVAP purge line, and all intake manifold vacuum connections. Install charge air cooler pipes to turbocharger and throttle body.
14. 14

    Install intake and exhaust systems
    Install exhaust downpipe to turbocharger with new gasket. Install turbocharger inlet and outlet pipes. Reconnect all remaining vacuum lines to intake system. Install air intake system from air box to turbocharger inlet. Verify all connections are secure and no vacuum lines are kinked or damaged.
15. 15

    Final assembly and fluid fill
    Reconnect all electrical connectors using labels and photos for reference. Install new oil filter. Install oil drain plug with new crush washer and torque to specification. Fill engine with 4.0 quarts Honda Genuine 0W-20 oil. Fill cooling system with Honda Type 2 coolant (blue), total capacity 6.0 quarts. Bleed cooling system by running engine with radiator cap off until thermostat opens. Install radiator, intercooler, and cooling fan assembly. Install undertray and engine cover. Reconnect battery negative terminal.
    ℹ️Cooling system may require multiple fill cycles to remove all air pockets.
    Torque spec

    Oil Drain Plug35 Nm (26 lb-ft)

Reassembly

1. Verify all electrical connectors are fully seated and locked
2. Check that all hose clamps are properly tightened
3. Verify serpentine belt routing matches underhood routing diagram
4. Ensure no tools or parts remain in engine bay
5. Double-check all fluid levels before starting engine

Verification

• Perform visual inspection for any disconnected hoses, wires, or loose components
• Check for fluid leaks around oil pan, valve cover, timing cover, and all coolant connections
• Start engine and listen for unusual noises - engine should idle smoothly without knocking or ticking
• Monitor oil pressure gauge - pressure should rise immediately upon startup
• Monitor coolant temperature gauge - should reach operating temperature and stabilize
• Check for exhaust leaks at turbocharger and downpipe connections
• Verify no check engine lights or warning indicators on dashboard
• Test drive vehicle and verify normal operation, smooth acceleration, and proper turbo boost
• Recheck all fluid levels after test drive and top off as needed
• Inspect for any new leaks after test drive
• Perform final torque check on critical fasteners after engine reaches operating temperature

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