Complete replacement of all valve springs on the 1.8L Nu engine, requiring removal of camshafts and timing components to access valve train.

Warnings

Tools required

Parts

• Valve springs (set of 16) × 1 — Use OEM specification
• Valve spring retainers (set of 16) × 1 — Use OEM specification
• Valve stem seals (set of 16) × 1 — Use OEM specification
• Valve cover gasket × 1 — 26441-2E000
• Valve cover spark plug tube seals × 1 — Set of 4
• Timing chain cover gasket × 1 — 21350-2E000
• Camshaft oil seals × 1 — Set of 2
• Engine oil × 1 — Kia Genuine 5W-20
• Engine coolant × 1 — Hyundai/Kia Long Life Green

Fluids

• Kia Genuine 5W-20 — 4.5 qt
• Hyundai/Kia Long Life Coolant (Green) — 2 qt

Preparation

1. Disconnect negative battery terminal and wait 3 minutes for airbag system to discharge
2. Remove engine cover by pulling upward on four attachment points
3. Drain engine coolant into appropriate container by opening radiator drain and lower radiator hose
4. Drain engine oil and remove oil filter
5. Remove air intake assembly from throttle body to air filter housing
6. Disconnect all electrical connectors from valve cover (ignition coils, VVT solenoid, sensors)
7. Label and photograph all vacuum hoses and electrical connections for reference
8. Support engine from above using engine support bar or hoist with load leveler
9. Remove right side engine mount to allow access to timing cover
10. Position cylinder #1 to TDC on compression stroke by aligning timing marks on crankshaft pulley

Procedure

1. 1

   Remove spark plugs and ignition coils
   Disconnect ignition coil electrical connectors. Remove coil mounting bolts and extract coils from valve cover. Using appropriate spark plug socket, remove all four spark plugs. Inspect plugs for fouling or damage and set aside in order.
   Torque spec

   Spark Plugs - Aluminum Head20 Nm (15 lb-ft)
2. 2

   Remove valve cover assembly
   Disconnect PCV hose and breather hose from valve cover. Remove valve cover bolts in reverse of tightening sequence (outside to inside pattern). Carefully lift valve cover off, breaking gasket seal with plastic pry tool if necessary. Remove and discard old gasket and spark plug tube seals.
   Torque spec

   Cover Bolts15 Nm (11 lb-ft)
3. 3

   Remove accessory drive belts and crankshaft pulley
   Remove serpentine belt by releasing tensioner. Remove crankshaft pulley center bolt (requires holding crankshaft with appropriate holding tool). Remove crankshaft pulley to access timing chain cover. Keep timing alignment marks visible on crankshaft.
4. 4

   Remove timing chain cover
   Remove timing chain cover mounting bolts in sequence. Note different bolt lengths and positions. Carefully separate cover from engine block, being careful not to damage sealing surfaces. Remove old gasket material completely.
   ⚠Cover bolts are different lengths. Document or photograph bolt positions before removal.
   Torque spec

   Cover Bolts15 Nm (11 lb-ft)

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

   Lock timing chain and mark positions
   Verify cylinder #1 is at TDC with timing marks aligned on camshaft sprockets and crankshaft. Use paint or marker to mark timing chain links at each sprocket timing mark. Install timing chain locking tool or wire tie to prevent chain from jumping teeth. Photograph timing alignment from multiple angles.
   ⚠️Accurate timing marks are critical. Take multiple photos and verify marks three times before proceeding.
6. 6

   Remove camshaft sprockets and timing chain
   Hold camshafts with appropriate holding tool to prevent rotation. Remove camshaft sprocket bolts from both intake and exhaust camshafts. Carefully remove sprockets while supporting timing chain. Remove timing chain guides and tensioner. Support timing chain to prevent falling into engine.
   ⚠Do not allow timing chain to fall into crankcase. Use wire or zip ties to support chain.
7. 7

   Remove camshaft bearing caps
   Loosen camshaft bearing cap bolts gradually in reverse sequence (outward from center) in 2-3 passes to prevent camshaft distortion. Mark each cap with cylinder number and position (intake/exhaust, front/rear). Caps are not interchangeable. Carefully lift camshafts from cylinder head, keeping them identified.
   ⚠Camshaft caps must be reinstalled in exact original positions. Improper installation will cause bearing failure and oil starvation.
   Torque spec

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

   Remove rocker arms and hydraulic lash adjusters
   Remove rocker arms from cylinder head, keeping them organized by cylinder number. Extract hydraulic lash adjusters (HLA) from their bores using magnetic tool. Store HLAs upright in clean engine oil to prevent air from entering. Label position of each component for reinstallation in same location.
   ℹ️Hydraulic lash adjusters must be stored upright in oil. If allowed to drain or lay on side, engine will be noisy on startup and may cause damage.
9. 9

   Compress and remove valve springs
   Install valve spring compressor on first valve spring. Compress spring carefully until retainer can be accessed. Use magnetic tool to remove valve keepers (collets). Slowly release spring tension and remove compressor. Remove valve spring retainer and valve spring. Remove and discard old valve stem seal. Repeat for all 16 valves, keeping components organized by cylinder and valve position.
   ⚠️Ensure valve spring compressor is properly seated before applying pressure. Springs under compression can cause serious injury if they slip.
   ⚠Valve keepers are small and easily lost. Use magnetic retrieval tool and work over clean area.
10. 10

    Inspect valves and cylinder head
    Inspect each valve stem for scoring, wear, or damage. Check valve faces for pitting or burning. Inspect cylinder head valve seats for damage. Clean all carbon deposits from valve stems and combustion chambers. Verify valve stem height is within specification. Inspect valve guides for excessive wear using dial indicator if available.
11. 11

    Install new valve stem seals and springs
    Install new valve stem seals onto valve guides using appropriate seal installation tool or deep socket. Ensure seals are fully seated. Install new valve spring over valve stem. Install valve spring retainer. Compress spring using valve spring compressor and install valve keepers into valve stem groove. Slowly release compressor and verify keepers are properly seated. Tap valve stem lightly with plastic hammer to ensure keepers are locked. Repeat for all 16 valves.
    ⚠Verify valve keepers are fully engaged in stem groove before releasing spring compressor. Improperly seated keepers will cause valve to drop into cylinder.
12. 12

    Reinstall rocker arms and hydraulic lash adjusters
    Install hydraulic lash adjusters into their original bores, ensuring they are fully seated. Install rocker arms in their original positions over lash adjusters and valve stems. Verify each rocker arm moves freely and contacts valve stem squarely.
13. 13

    Install camshafts and bearing caps
    Lubricate camshaft journals and lobes with clean engine oil. Install camshafts into cylinder head in correct positions (intake/exhaust). Install camshaft bearing caps in their original marked positions with arrows pointing toward timing belt end. Install cap bolts finger tight. Tighten cap bolts in sequence from center outward in 2-3 progressive passes to specified torque. Verify camshafts rotate freely by hand.
    ⚠Tighten camshaft cap bolts gradually in multiple passes. Uneven tightening will warp camshaft and cause bearing failure.
    Torque spec

    Camshaft Cap Bolts14 Nm (10 lb-ft)
14. 14

    Reinstall timing chain and components
    Position crankshaft to TDC mark. Install timing chain guides and tensioner (tensioner in released position). Route timing chain over crankshaft sprocket and install camshaft sprockets with timing marks aligned to marked chain links. Verify all timing marks align correctly with chain installed. Install and torque camshaft sprocket bolts while holding camshafts. Release timing chain tensioner. Rotate engine two complete revolutions by hand and verify timing marks realign perfectly.
    ⚠️Verify timing alignment is perfect before proceeding. Incorrect timing will cause immediate catastrophic engine damage on startup.
15. 15

    Install timing cover and remaining components
    Install new timing chain cover gasket. Install timing cover and torque bolts to specification in sequence. Install crankshaft pulley and torque center bolt. Install accessory drive belt. Install new valve cover gasket and spark plug tube seals. Install valve cover and torque bolts in sequence from center outward. Reinstall engine mount. Apply anti-seize to spark plug threads and install spark plugs to specification. Reinstall ignition coils and reconnect all electrical connections.
    Torque spec

    Cover Bolts15 Nm (11 lb-ft)

    Mounting Bolts26 Nm (19 lb-ft)

    Spark Plugs - Aluminum Head20 Nm (15 lb-ft)

Reassembly

1. Reinstall air intake assembly and secure all clamps
2. Fill engine with 4.5 quarts of Kia Genuine 5W-20 engine oil and install new oil filter
3. Refill cooling system with Hyundai/Kia Long Life Green coolant mixture, bleed air from system
4. Reconnect negative battery terminal
5. Double-check all electrical connectors, hoses, and fasteners are properly secured

Verification

• Before starting engine, rotate crankshaft by hand two complete revolutions to verify no interference or binding
• Verify timing marks align correctly after manual rotation
• Start engine and listen for unusual noises, valve train noise should be minimal after 30 seconds as HLAs pump up
• Check for oil leaks at valve cover, timing cover, and camshaft seals
• Check for coolant leaks at all disturbed connections
• Allow engine to reach operating temperature and verify smooth idle and proper operation
• Test drive vehicle and verify normal power delivery and no misfires
• Recheck valve cover bolt torque after engine has cooled completely
• Monitor oil level and condition for first 100 miles for any contamination or excessive consumption

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