Remove, machine, and reinstall the cylinder head on a 2015 Kia Forte 1.8L I4 engine to restore proper sealing surface after warping or gasket failure.

Warnings

Tools required

Parts

• Cylinder head gasket × 1 — Use OEM Kia specification
• Cylinder head bolts (TTY) × 10 — Use OEM - not reusable
• Valve cover gasket × 1 — Use OEM specification
• Intake manifold gasket × 1 — Use OEM specification
• Exhaust manifold gasket × 1 — Use OEM specification
• Timing chain cover gasket × 1 — Use OEM specification
• Spark plugs × 4 — Replace during reassembly
• Anti-seize compound × 1 — For exhaust manifold studs

Fluids

• Kia Genuine 5W-20 Engine Oil — 4.5 qt
• Hyundai/Kia Long Life Coolant (Green) — 7.5 qt

Preparation

1. Verify engine is completely cool to touch
2. Disconnect negative battery cable and isolate
3. Drain engine coolant completely into appropriate container
4. Drain engine oil and remove oil filter
5. Remove engine cover and air intake system
6. Label all electrical connectors, vacuum lines, and hoses before disconnection
7. Take photos of timing chain alignment marks before disassembly
8. Support engine from above with hoist or install engine support fixture across fender rails

Procedure

1. 1

   Remove valve cover and accessory components
   Disconnect ignition coils and all electrical connectors from valve cover area. Remove PCV hoses and breather tubes. Remove valve cover bolts in reverse of tightening sequence (outside to inside pattern). Lift valve cover away and inspect gasket condition. Remove spark plugs and store safely.
   Torque spec

   Cover Bolts15 Nm (11 lb-ft)
2. 2

   Remove intake and exhaust manifolds
   Disconnect throttle body and all intake manifold connections including fuel lines (relieve fuel pressure first), vacuum lines, and sensors. Remove intake manifold bolts and set manifold aside. Disconnect exhaust manifold from downpipe. Remove exhaust manifold heat shield. Remove exhaust manifold nuts working from center outward. Note that studs may need replacement if damaged.
   ⚠️Relieve fuel system pressure before disconnecting fuel lines. Fuel spray can cause fire or injury.
   Torque spec

   Intake Manifold Bolts25 Nm (18 lb-ft)

   Exhaust Manifold Nuts30 Nm (22 lb-ft)
3. 3

   Remove timing chain cover and set timing position
   Remove accessory drive belts. Remove crankshaft pulley bolt and pulley. Remove timing chain cover bolts in sequence. Rotate crankshaft to TDC cylinder #1 (align timing marks on crankshaft and camshaft sprockets). Mark chain-to-sprocket relationship with paint pen. Install timing chain locking tool or zip-tie chain to sprockets to maintain relationship.
   ⚠Document all timing marks with photos before proceeding. Incorrect timing will destroy the engine.
   Torque spec

   Cover Bolts15 Nm (11 lb-ft)
4. 4

   Remove camshaft(s) and timing components
   Loosen camshaft bearing cap bolts gradually in reverse order (inside-out, multiple passes) to prevent warping. Remove camshaft bearing caps keeping them in order for reinstallation. Lift camshaft(s) out carefully. Remove camshaft sprocket bolts and sprockets while keeping chain supported. Remove timing chain tensioner and guides. Keep all components organized by position.
   Torque spec

   Mounting Bolts26 Nm (19 lb-ft)
5. 5

   Remove cylinder head bolts and head
   Remove cylinder head bolts in reverse of tightening sequence (outside to inside, spiral pattern). Start from outermost bolts and work inward in multiple passes. Once all bolts are removed, discard them (TTY bolts cannot be reused). Gently break head seal using plastic pry bar at designated lift points only - never between sealing surfaces. Lift cylinder head straight up to avoid damaging block surface. Place head on clean wooden blocks with combustion chamber side up.
   ⚠️Do not reuse cylinder head bolts. These are torque-to-yield bolts that stretch during installation and will fail if reused.
   Torque spec

   Cylinder Head Bolts65 Nm (48 lb-ft)
6. 6

   Inspect and prepare for machining
   Inspect cylinder head for cracks using dye penetrant or magnaflux if available. Check for warpage using precision straightedge and feeler gauge - maximum allowable warpage is 0.05mm. Measure head height at multiple points; minimum height after machining is 131.8mm. Remove all valves using valve spring compressor if complete inspection is needed. Transport head to machine shop for resurfacing. Specify maximum material removal of 0.2mm.
7. 7

   Clean and prepare block surface
   Thoroughly clean cylinder head gasket surface on engine block using plastic scraper only. Remove all old gasket material completely. Clean bolt holes using brake cleaner and compressed air - ensure no oil or debris remains as this affects torque accuracy. Stuff clean rags into cylinders and coolant passages to prevent debris entry. Inspect block surface for damage or warpage. Check that dowel pins are present and undamaged.
   ⚠Never use metal scrapers on aluminum block surface. Scratches will cause gasket leaks.
8. 8

   Install resurfaced cylinder head
   Verify machined head meets specifications and all valve components are properly installed if disassembled. Remove all protective rags from block. Place new head gasket on block ensuring all alignment dowels engage properly and gasket orientation is correct (TOP marking faces up). Carefully lower cylinder head onto block, aligning with dowel pins. Install NEW cylinder head bolts finger-tight in all positions. Do not apply oil to bolt threads unless specified - install dry.
   ⚠️Verify you are using NEW cylinder head bolts. Using old TTY bolts will result in engine failure.
   Torque spec

   Cylinder Head Bolts65 Nm (48 lb-ft)
9. 9

   Torque cylinder head bolts to specification
   Torque cylinder head bolts in three stages following the correct sequence (start at center, spiral outward): Stage 1 - Torque all bolts to 65 Nm (48 lb-ft) in sequence. Stage 2 - Loosen all bolts completely in reverse sequence. Stage 3 - Re-torque to 65 Nm (48 lb-ft) in sequence. Stage 4 - Using angle gauge, rotate each bolt an additional 90 degrees in sequence. Stage 5 - Rotate each bolt another 90 degrees (180 degrees total angle) in sequence. Verify all bolts have been angle-torqued properly.
   ⚠Follow torque sequence exactly. Improper sequence will warp the head and cause immediate failure.
   Torque spec

   Cylinder Head Bolts65 Nm (48 lb-ft)
10. 10

    Reinstall camshaft and timing components
    Apply clean engine oil to camshaft journals and lobes. Install camshaft(s) in original position. Install bearing caps in correct order and orientation. Tighten bearing cap bolts gradually in sequence (inside-out) to specification. Install timing chain guides and tensioner. Align camshaft sprockets with timing marks and install on camshafts while maintaining chain position. Verify all timing marks align correctly at TDC. Install sprocket bolts and torque to specification. Remove timing chain locking tool and rotate engine two full revolutions by hand, verifying timing marks realign.
    ⚠Rotate engine by hand ONLY. Do not use starter. Listen and feel for any interference indicating incorrect timing.
    Torque spec

    Mounting Bolts26 Nm (19 lb-ft)
11. 11

    Reinstall timing cover and accessories
    Clean timing cover mating surfaces thoroughly. Install new timing cover gasket or apply appropriate RTV sealant per Kia specifications. Install timing cover and torque bolts in correct sequence. Install crankshaft pulley and torque bolt to specification. Reinstall accessory drive belts and adjust tension properly.
    Torque spec

    Cover Bolts15 Nm (11 lb-ft)

    Mounting Bolts26 Nm (19 lb-ft)
12. 12

    Reinstall exhaust and intake manifolds
    Install new exhaust manifold gasket. Apply anti-seize compound to exhaust manifold studs. Install exhaust manifold and torque nuts to 30 Nm (22 lb-ft) working from center outward (hot to cold pattern). Install heat shield. Connect exhaust downpipe. Install new intake manifold gasket. Position intake manifold and torque bolts to 25 Nm (18 lb-ft) in proper sequence. Reconnect all fuel lines, vacuum lines, throttle body, and sensors.
    ⚠Exhaust manifold must be torqued in correct sequence (center outward) to prevent warping and exhaust leaks.
    Torque spec

    Exhaust Manifold Nuts30 Nm (22 lb-ft)

    Intake Manifold Bolts25 Nm (18 lb-ft)
13. 13

    Reinstall valve cover and finalize assembly
    Install new spark plugs and torque to specification. Clean valve cover mating surface thoroughly. Install new valve cover gasket ensuring proper seating in groove. Position valve cover and install bolts finger-tight. Torque valve cover bolts to 10 Nm (7 lb-ft) in correct sequence (inside to outside pattern). Reconnect all electrical connectors including ignition coils. Reconnect PCV and breather hoses. Reinstall air intake system and engine cover.
    Torque spec

    Cover Bolts15 Nm (11 lb-ft)

    Sensor Bolts10 Nm (8 lb-ft)
14. 14

    Refill fluids and final checks
    Install new oil filter and refill engine with 4.5 quarts Kia Genuine 5W-20 oil. Refill cooling system with 7.5 quarts Hyundai/Kia Long Life Coolant (Green), bleeding air from system per factory procedure. Reconnect negative battery cable. Double-check all connections, bolts, and hoses. Verify no tools or parts are left in engine bay.

Reassembly

1. Torque all fasteners to specified values using calibrated torque wrench
2. Replace all gaskets and seals with new OEM parts
3. Use NEW cylinder head bolts - never reuse TTY bolts
4. Follow exact torque sequences for cylinder head, camshaft caps, and valve cover
5. Apply anti-seize only to exhaust manifold studs as specified
6. Verify timing chain alignment before and after rotating engine by hand

Verification

• Rotate engine by hand at least two complete revolutions to verify no binding or interference
• Verify all timing marks realign correctly after two full rotations
• Check for any fluid leaks around head gasket, timing cover, valve cover, and manifolds before starting
• Start engine and listen for any abnormal noises indicating timing or clearance issues
• Monitor for leaks during initial warm-up cycle
• Verify engine reaches normal operating temperature and cooling fans cycle properly
• Check oil level and coolant level after warm-up and top off as needed
• Allow engine to fully warm up, then re-check all torque values on head bolts after cool-down (some manufacturers require this)
• Perform test drive and monitor engine performance, oil pressure, and temperature
• Inspect for any leaks after test drive and recheck fluid levels

More procedures for this vehicle