Complete removal and replacement of the cylinder head assembly on a 2015 Kia Forte 1.8L I4 engine, including timing chain removal, valve train disassembly, and head gasket replacement.

Warnings

Tools required

Parts

• Cylinder head gasket × 1 — Use OEM specification
• Cylinder head bolts (TTY) × 10 — Use OEM specification - NOT reusable
• Valve cover gasket × 1 — Use OEM specification
• Timing cover gasket × 1 — Use OEM specification
• Exhaust manifold gasket × 1 — Use OEM specification
• Intake manifold gasket × 1 — Use OEM specification
• Oil drain plug crush washer × 1 — Use OEM specification
• Thermostat O-ring × 1 — Use OEM specification
• Camshaft oil seal × 1 — Use OEM specification
• Engine oil filter × 1 — Use OEM specification

Fluids

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

Preparation

1. Ensure engine is completely cool before starting work
2. Disconnect negative battery cable and secure away from battery post
3. Remove engine cover and intake air duct assembly
4. Drain engine coolant completely into appropriate container by removing radiator drain plug and lower radiator hose
5. Drain engine oil and remove oil filter
6. Label and photograph all vacuum lines, electrical connections, and hose routing for reference during reassembly
7. Support engine from above using engine support fixture or from below with floor jack and wood block under oil pan

Procedure

1. 1

   Remove accessory components and upper engine covers
   Disconnect all electrical connectors from ignition coils, fuel injectors, and engine sensors. Remove ignition coils and spark plugs. Disconnect throttle body connector, PCV hoses, and brake booster vacuum line. Remove engine wiring harness from valve cover area and secure out of the way. Remove air cleaner assembly completely.
2. 2

   Remove intake and exhaust manifolds
   Disconnect fuel line at fuel rail (release pressure first by removing fuel pump fuse and cranking engine). Remove intake manifold bolts and carefully lift manifold away with fuel rail attached. Disconnect exhaust manifold from exhaust pipe at flange. Remove exhaust manifold heat shield. Remove exhaust manifold nuts working from hot (center) to cold (outer) areas. Note anti-seize application points for reassembly.
   Torque spec

   Intake Manifold Bolts25 Nm (18 lb-ft)

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

   Remove valve cover and accessory drive components
   Remove valve cover bolts in reverse of tightening sequence. Carefully lift valve cover away and remove gasket. Remove drive belt. Remove any accessory brackets attached to cylinder head or timing cover that will interfere with removal. Disconnect coolant hoses from thermostat housing.
   Torque spec

   Cover Bolts15 Nm (11 lb-ft)

   Thermostat Housing Bolts15 Nm (11 lb-ft)
4. 4

   Position engine to TDC and mark timing components
   Rotate crankshaft clockwise using bolt at front of crankshaft until cylinder #1 is at Top Dead Center (TDC) on compression stroke. Verify timing marks on camshaft sprockets align with marks on timing cover or head. Use paint marker or scribe to mark exact position of timing chain to camshaft sprockets and crankshaft sprocket. Take detailed photographs of timing marks and chain routing around all guides.
   ⚠This is the most critical step. Incorrect timing marks will result in engine damage. Triple-check all alignment marks before proceeding.
5. 5

   Remove timing cover and timing chain tensioner
   Remove timing chain cover bolts (8mm size) following reverse of tightening sequence. Carefully pry cover away using plastic pry tool at designated pry points. Remove timing chain tensioner bolt and extract tensioner assembly. Note the installed position of tensioner and any retaining pin or clip mechanism. Verify chain slack increases when tensioner is removed.
   Torque spec

   Cover Bolts15 Nm (11 lb-ft)

   Timing Chain Tensioner Bolt25 Nm (18 lb-ft)
6. 6

   Remove camshaft sprockets and timing chain
   Hold each camshaft in position using wrench on hex section of camshaft (typically between lobes). Remove camshaft sprocket bolts. Carefully slide sprockets forward off camshafts while supporting timing chain. Remove timing chain from crankshaft sprocket. If removing timing chain guides, remove guide bolts and extract guides. Inspect all timing components for wear, particularly chain guides and tensioner shoe.
   ⚠Do not allow camshafts to rotate once sprockets are removed. Secure camshafts in position or note cam lobe positions relative to valves.
   Torque spec

   Camshaft Sprocket Bolt80 Nm (59 lb-ft)

   Timing Chain Guide Bolts12 Nm (9 lb-ft)
7. 7

   Remove camshaft bearing caps and camshafts
   Loosen camshaft bearing cap bolts gradually in reverse order of tightening sequence (outward from center), making multiple passes to prevent warping. Remove bearing caps and keep in exact order with bolts in their original positions. Carefully lift camshafts straight up from head. Mark intake and exhaust camshafts clearly. Inspect camshaft lobes and journals for wear or damage. Keep rocker arms or lifters in order if removed.
   ⚠Camshaft bearing caps are directional and position-specific. Mark each cap with cylinder number and orientation before removal.
   Torque spec

   Camshaft Bearing Cap Bolts14 Nm (10 lb-ft)
8. 8

   Remove cylinder head bolts and cylinder head
   Loosen cylinder head bolts in reverse order of tightening sequence, working from outer bolts toward center. Make multiple passes, loosening each bolt 1/4 turn at a time to prevent warping. Remove all cylinder head bolts and discard (TTY bolts not reusable). Check for any remaining hoses, wires, or brackets attached to head. Carefully lift cylinder head straight up from engine block. If head is stuck, gently tap with rubber mallet at designated areas - never pry between head and block surfaces.
   ⚠️Cylinder head is extremely heavy (approximately 40-50 lbs). Use proper lifting technique or have assistant help to prevent injury or dropping head.
   Torque spec

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

   Clean all mating surfaces and inspect components
   Remove old head gasket from block and any gasket material from both cylinder head and engine block surfaces using plastic scraper only (never metal). Clean surfaces with brake cleaner and lint-free cloth. Inspect engine block surface for warpage, damage, or debris in cylinders. Cover cylinders with clean cloth to prevent debris entry. Have cylinder head professionally machined if warpage exceeds specification. Check cylinder head for cracks using dye penetrant or magnetic particle testing if suspected. Inspect valves, springs, and seats. Clean all oil passages in cylinder head.
   ⚠Any debris left on mating surfaces or falling into cylinders will cause immediate engine damage. Ensure surfaces are perfectly clean.
10. 10

    Install cylinder head with new gasket
    Verify engine block and cylinder head surfaces are completely clean and dry. Install new cylinder head gasket on block with proper orientation (UP mark facing cylinder head). Check that all coolant and oil passage holes align correctly. Carefully lower cylinder head onto block, ensuring gasket does not shift. Install NEW cylinder head bolts finger-tight in proper sequence. Using torque wrench, tighten all bolts to 65 Nm (48 lb-ft) in proper sequence. Then tighten all bolts an additional 90 degrees using angle gauge in same sequence. Finally, tighten all bolts an additional 45 degrees in sequence for total of 135 degrees angle tightening.
    ⚠️Absolutely critical: Use ONLY new cylinder head bolts. Tighten in exact sequence with torque wrench AND angle gauge. Improper tightening will cause head gasket failure and potential engine damage.
    Torque spec

    Cylinder Head Bolts65 Nm (48 lb-ft)
11. 11

    Install camshafts and bearing caps
    Lubricate all camshaft journals and lobes with clean engine oil. Install camshafts in correct positions (intake and exhaust marked from removal). Verify camshaft lobes are positioned properly relative to valve positions. Apply small amount of engine oil to bearing cap contact surfaces. Install bearing caps in exact original positions with directional markings correct. Install bearing cap bolts and tighten in sequence from center outward in 3 passes: first pass to 5 Nm, second pass to 10 Nm, final pass to 14 Nm (10 lb-ft). Verify camshafts rotate freely by hand after installation.
    ⚠Ensure cam lobes are not pressing directly on valve shims during cap installation to prevent valve train damage.
    Torque spec

    Camshaft Bearing Cap Bolts14 Nm (10 lb-ft)
12. 12

    Install timing chain, guides, and sprockets
    If removed, install timing chain guides and tighten guide bolts to specification. Verify crankshaft is still at TDC mark. Route timing chain over crankshaft sprocket according to marked positions from disassembly. Install camshaft sprockets onto camshafts while aligning timing chain with marks made during removal. Hold each camshaft with wrench on hex section and tighten sprocket bolts to 80 Nm (59 lb-ft). Double-check all timing marks align correctly with TDC position. Install new camshaft oil seal if needed.
    ⚠️Verify timing marks are EXACTLY aligned before proceeding. Rotate engine by hand 2 complete revolutions and recheck timing marks align at TDC. Incorrect timing will destroy engine.
    Torque spec

    Camshaft Sprocket Bolt80 Nm (59 lb-ft)

    Timing Chain Guide Bolts12 Nm (9 lb-ft)
13. 13

    Install timing chain tensioner and timing cover
    Compress timing chain tensioner and install retaining pin or clip to hold in compressed position. Install tensioner into engine and tighten tensioner bolt to 25 Nm (18 lb-ft). Clean timing cover mating surface and install new timing cover gasket. Apply small bead of RTV sealant at corners where cover meets cylinder head to block joint if specified. Install timing cover and tighten 8mm bolts in sequence to 25 Nm (18 lb-ft). Remove tensioner retaining pin to activate tensioner. Rotate crankshaft 2 full revolutions clockwise and verify timing marks realign and chain has proper tension.
    Torque spec

    Timing Chain Tensioner Bolt25 Nm (18 lb-ft)

    Cover Bolts15 Nm (11 lb-ft)
14. 14

    Reinstall remaining components and refill fluids
    Install new valve cover gasket. Install valve cover and tighten bolts in sequence to 10 Nm (7 lb-ft). Install thermostat with new O-ring and tighten housing bolts to 15 Nm (11 lb-ft). Install exhaust manifold with new gasket, applying anti-seize to stud threads, and tighten nuts from hot to cold to 30 Nm (22 lb-ft). Install intake manifold with new gasket and tighten bolts to 25 Nm (18 lb-ft). Reconnect all coolant hoses, vacuum lines, and electrical connections per photographs taken during disassembly. Install new oil filter. Install oil drain plug with new crush washer and tighten to 35 Nm (26 lb-ft). Fill engine with 4.5 quarts of Kia Genuine 5W-20 engine oil. Fill cooling system with 7.5 quarts of Hyundai/Kia Long Life Green coolant. Reinstall spark plugs, ignition coils, and all remaining components.
    Torque spec

    Cover Bolts15 Nm (11 lb-ft)

    Thermostat Housing Bolts15 Nm (11 lb-ft)

    Exhaust Manifold Nuts30 Nm (22 lb-ft)

    Intake Manifold Bolts25 Nm (18 lb-ft)

    Oil Drain Plug35 Nm (26 lb-ft)

Reassembly

1. Ensure all electrical connectors are fully seated and locked in place
2. Verify all vacuum lines and hoses are properly routed and secured per factory routing
3. Double-check that no tools or rags were left in engine compartment
4. Ensure all coolant hose clamps are properly tightened
5. Reconnect negative battery cable

Verification

• Before starting engine, remove spark plugs and crank engine for 10 seconds to build oil pressure and verify timing is correct by watching valve movement
• Reinstall spark plugs and start engine. Listen for any unusual noises immediately
• Check for oil leaks around valve cover, timing cover, and cylinder head gasket areas
• Check for coolant leaks at all hose connections and cylinder head gasket areas
• Allow engine to reach normal operating temperature and verify cooling system is functioning properly with no overheating
• After engine reaches operating temperature, check coolant level and top off as needed. Burp cooling system of air pockets
• Monitor for any oil or coolant consumption over first 100 miles of operation
• Perform idle relearn procedure if equipped with electronic throttle control
• After 500 miles, check valve cover and all gasket areas for any seepage or leaks

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