This procedure replaces the timing chain, guides, tensioners, and related components on the 2014-2018 Chevrolet Silverado 1500 5.3L V8 L83 engine to restore proper valve timing and eliminate timing chain wear.

Warnings

Tools required

Parts

• Timing chain kit (includes chains, guides, tensioners, sprockets) × 1 — ACDelco 12681875 or equivalent
• Timing cover gasket × 1 — Use OEM specification
• Front crankshaft seal × 1 — Use OEM specification
• Valve cover gaskets (both banks) × 2 — Use OEM specification
• Valve cover grommets and seals × 1 — Use OEM specification
• Water pump gasket (if disturbed) × 1 — Use OEM specification
• Oil pump O-ring × 1 — Use OEM specification
• RTV silicone sealant (GM approved) × 1 — GM 12378521 or equivalent
• Engine oil and filter × 1 — ACDelco PF63E filter
• Coolant (DEX-COOL) × 1 — ACDelco 10-5027

Fluids

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

Preparation

1. Disconnect negative battery cable and wait 15 minutes for airbag system to discharge
2. Drain engine oil completely and remove oil filter
3. Drain cooling system into suitable container for reuse or disposal
4. Remove engine cover and air intake assembly
5. Remove radiator and cooling fan assembly for access
6. Support engine with engine support fixture from above or floor jack with block of wood under oil pan
7. Relieve fuel system pressure if fuel lines will be disturbed
8. Tag and photograph all electrical connections and vacuum lines before removal
9. Clean engine exterior around timing cover area to prevent contamination

Procedure

1. 1

   Remove valve covers and accessory drive components
   Disconnect ignition coils and injector harnesses. Remove both valve covers, marking which belongs to which bank. Remove serpentine belt, alternator, power steering pump (support aside without disconnecting lines), A/C compressor (support aside), and water pump. Remove crankshaft pulley using harmonic balancer puller after removing center bolt.
   Torque spec

   Cover Bolts20 Nm (15 lb-ft)

   Crankshaft Pulley Bolt180 Nm (133 lb-ft)
2. 2

   Remove engine mount and timing cover
   Remove right side engine mount to allow engine to be lowered slightly for timing cover clearance. Remove all timing cover bolts, noting there are three different sizes (6mm, 8mm, and 10mm). Carefully pry timing cover away from block using plastic pry points only. Remove and discard timing cover gasket and front crankshaft seal.
   Torque spec

   Cover Bolts20 Nm (15 lb-ft)

   Mounting Bolts60 Nm (44 lb-ft)
3. 3

   Verify TDC position and mark components
   Rotate crankshaft clockwise until cylinder #1 is at TDC (both intake and exhaust valves closed, piston at top). Verify timing marks on all sprockets align with their respective marks. Use paint marker or scribe to mark cam phaser positions relative to cylinder heads before removal. Photograph all timing marks and chain positions.
   ⚠This is the last opportunity to verify correct timing before disassembly. Document everything thoroughly.
4. 4

   Remove cam phasers and camshaft sprockets
   Hold each camshaft stationary using a wrench on the camshaft hex (located behind the cam phaser). Remove cam phaser bolts from all four camshafts. Remove cam phasers, keeping them organized by position. Remove camshaft sprocket bolts while holding camshaft hex. Remove all four camshaft sprockets.
   ⚠Do not allow camshafts to rotate during bolt removal or timing may be lost.
   Torque spec

   Cam Phaser Bolt65 Nm (48 lb-ft)

   Camshaft Sprocket Bolt80 Nm (59 lb-ft)
5. 5

   Remove secondary timing chains
   Compress both secondary timing chain tensioners and install retaining pins (paperclip or special tool) to hold them compressed. Remove tensioner bolts and remove tensioners. Remove secondary chain guide bolts. Remove both secondary timing chains from the camshaft sprockets and oil pump drive sprocket. Keep left and right chains separate if reusing any components.
   Torque spec

   Tensioner Bolt25 Nm (19 lb-ft)

   Guide Bolts31 Nm (23 lb-ft)
6. 6

   Remove primary timing chain assembly
   Remove primary timing chain tensioner by compressing and removing bolt. Remove primary timing chain idler sprocket bolt. Remove primary chain guides. Remove primary timing chain from crankshaft sprocket and idler sprocket. Remove crankshaft sprocket if replacing (some kits include new sprocket).
   Torque spec

   Timing Chain Idler Sprocket25 Nm (18 lb-ft)

   Tensioner Bolt25 Nm (19 lb-ft)

   Guide Bolts31 Nm (23 lb-ft)
7. 7

   Inspect and prepare components
   Inspect oil pump drive sprocket for wear. Check camshaft and crankshaft sprocket mounting surfaces for damage. Thoroughly clean all timing cover mating surfaces on engine block and cylinder heads using plastic scraper. Remove all old RTV and gasket material. Clean oil passages in block. Inspect oil pump pickup screen and clean if necessary.
   ℹ️Any metal debris found indicates component failure. Inspect oil pan for metal shavings and consider oil system flush.
8. 8

   Install crankshaft sprocket and primary chain
   Install new or cleaned crankshaft sprocket with timing mark facing out. Route new primary timing chain around crankshaft sprocket with bright or colored link aligned with crankshaft timing mark. Install idler sprocket with chain routed around it, aligning timing marks. Install idler sprocket bolt finger tight. Install primary chain guides and tighten bolts.
   Torque spec

   Timing Chain Idler Sprocket25 Nm (18 lb-ft)

   Guide Bolts31 Nm (23 lb-ft)
9. 9

   Install primary chain tensioner
   Compress new primary timing chain tensioner and install retaining pin to hold it compressed. Install tensioner to block and tighten bolt. Do not release tensioner pin yet. Verify primary chain has no slack and all timing marks are aligned.
   Torque spec

   Tensioner Bolt25 Nm (19 lb-ft)
10. 10

    Install camshaft sprockets and secondary chains
    Install camshaft sprockets onto camshafts without chains first to verify fit. Remove sprockets and route new secondary timing chains around appropriate camshaft sprockets, aligning colored links with sprocket timing marks. Install sprockets with chains onto camshafts, routing chains around oil pump drive sprocket (center sprocket). Hold camshafts on hex and install sprocket bolts. Verify all timing marks align correctly.
    ⚠Each bank has specific intake and exhaust chain routing. Refer to service manual diagram for exact chain path.
    Torque spec

    Camshaft Sprocket Bolt80 Nm (59 lb-ft)
11. 11

    Install secondary chain guides and tensioners
    Install new secondary chain guides to cylinder heads and tighten guide bolts. Compress new secondary chain tensioners and install retaining pins. Install both tensioners and tighten bolts. Verify all chains are properly seated on sprockets and guides before releasing tensioner pins.
    Torque spec

    Guide Bolts31 Nm (23 lb-ft)

    Tensioner Bolt25 Nm (19 lb-ft)
12. 12

    Install cam phasers
    Apply medium-strength threadlocker to cam phaser bolts. Install cam phasers in their original orientations (reference marks made during disassembly). Hold each camshaft on hex and tighten phaser bolts to specification in a cross pattern if multiple bolts per phaser.
    ⚠Cam phasers must be installed in correct rotational position or engine will not run properly.
    Torque spec

    Cam Phaser Bolt65 Nm (48 lb-ft)
13. 13

    Release tensioners and verify timing
    Carefully remove retaining pins from all three timing chain tensioners (two secondary, one primary). Verify tensioners extend and apply proper tension. Manually rotate crankshaft two complete revolutions clockwise (viewed from front) using breaker bar on crankshaft bolt. Verify all timing marks realign at TDC cylinder #1. Check that no valves contact pistons by feeling for resistance (should rotate smoothly).
    ⚠️If any binding or hard stops are felt while rotating engine, STOP immediately. Timing is incorrect and valve-to-piston contact will occur.
14. 14

    Install timing cover and front seal
    Install new oil pump O-ring. Apply thin bead of GM-approved RTV silicone to engine block timing cover mating surface at areas specified in service manual (typically block-to-oil pan junction and block-to-head junctions). Install new timing cover gasket. Press new front crankshaft seal into timing cover using seal driver. Install timing cover and hand-start all bolts. Tighten bolts in sequence: first 6mm bolts, then 8mm bolts, then 10mm bolts to their respective torque specifications.
    Torque spec

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

    Reinstall accessories and valve covers
    Install crankshaft pulley with new bolt (if TTY type) and torque to specification, using holding tool to prevent rotation. Reinstall water pump with new gasket, A/C compressor, power steering pump, and alternator. Install new valve cover gaskets and grommets. Install valve covers and torque bolts in sequence from center outward. Reinstall engine mount. Reconnect all electrical connections and vacuum lines. Install serpentine belt.
    Torque spec

    Crankshaft Pulley Bolt180 Nm (133 lb-ft)

    Cover Bolts20 Nm (15 lb-ft)

    Mounting Bolts60 Nm (44 lb-ft)

Reassembly

1. Reinstall radiator and cooling fan assembly
2. Reinstall air intake system and engine cover
3. Refill cooling system with fresh DEX-COOL coolant and bleed air from system
4. Install new oil filter and refill engine with 8.5 quarts dexos1 0W-20 oil
5. Reconnect negative battery cable
6. Double-check that all electrical connections, vacuum lines, and hoses are reconnected

Verification

• Start engine and verify it starts normally without unusual noises or timing-related fault codes
• Allow engine to reach operating temperature and verify no coolant or oil leaks from timing cover area
• Check for proper oil pressure on instrument cluster (should reach normal pressure within 5 seconds)
• Listen for timing chain noise - properly installed chains should be nearly silent at idle and all RPM ranges
• Scan for diagnostic trouble codes related to cam/crank correlation - there should be none
• Verify smooth idle and proper throttle response without misfires or hesitation
• Road test vehicle under various load conditions to verify proper engine performance and cam phaser operation
• Recheck oil and coolant levels after test drive and verify no leaks
• Monitor engine for first 500 miles for any unusual noises or performance issues

More procedures for this vehicle