Complete replacement of the timing chain, guides, tensioners, and sprockets on the 6.7L Cummins diesel engine, requiring front-end disassembly and precise timing alignment.

Warnings

Tools required

Parts

• Timing chain kit (includes chain, guides, tensioner) × 1 — Use OEM Cummins specification
• Crankshaft front seal × 1 — Use OEM specification
• Camshaft seal × 1 — Use OEM specification
• Timing cover gasket × 1 — Use OEM specification
• Valve cover gasket × 1 — Use OEM specification
• Oil drain plug crush washer × 1 — Use OEM specification
• Engine oil filter × 1 — Mopar 68197867AA or equivalent
• Fuel filter/water separator × 1 — Mopar 68157291AA or equivalent
• Serpentine belt × 1 — Use OEM specification
• RTV silicone sealant × 1 — Mopar approved grey RTV

Fluids

• Mopar 5W-20 Synthetic Blend — 13 qt
• Mopar OAT Coolant (Purple) — 18 qt

Preparation

1. Park vehicle on level surface and engage parking brake. Chock rear wheels securely.
2. Disconnect both battery cables (negative first) and remove batteries from vehicle for access.
3. Drain engine coolant completely from radiator and block drain plugs into appropriate container.
4. Drain engine oil and remove oil filter. Install drain plug with new crush washer torqued to specification.
5. Remove hood for overhead clearance and access.
6. Remove upper and lower radiator hoses, overflow tank, and radiator support brackets.
7. Remove engine cooling fan assembly and fan shroud.
8. Remove radiator and A/C condenser assembly after disconnecting transmission cooler lines.
9. Remove serpentine belt and all belt-driven accessories (alternator, A/C compressor, power steering pump). Support accessories aside without disconnecting hoses where possible.
10. Install engine support fixture or attach engine hoist to lifting eyes on engine.
11. Remove front motor mount bolts and raise engine approximately 2 inches for timing cover clearance.

Procedure

1. 1

   Remove crankshaft pulley and harmonic balancer
   Use crankshaft holding tool or insert barring tool through bell housing to lock crankshaft rotation. Remove crankshaft pulley bolt using impact wrench (180 Nm installation torque). Use harmonic balancer puller to remove balancer from crankshaft snout. Do not pry or hammer on balancer as this will damage crankshaft.
   Torque spec

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

   Remove valve cover and verify TDC position
   Remove valve cover bolts in reverse of tightening sequence. Lift valve cover away and set aside with gasket. Rotate crankshaft to TDC position for cylinder #1 (compression stroke). Verify timing marks on camshaft gear align with marks on engine block or head. Mark crankshaft position with paint or marker for reference.
   ⚠Valve cover gasket is reusable if not damaged, but replacement is recommended during this service.
   Torque spec

   Valve Cover Bolts10 Nm (7 lb-ft)
3. 3

   Remove timing cover
   Remove all timing cover bolts, noting locations of different bolt lengths and sizes (6mm, 8mm, and 10mm variants). Carefully separate timing cover from engine block using plastic wedges or gasket scraper. Do not pry against sealing surfaces. Remove timing cover along with any attached oil pump pickup if applicable. Clean all gasket surfaces thoroughly with gasket scraper and brake cleaner.
   ℹ️Keep all timing cover bolts organized by size and location. They are not interchangeable.
   Torque spec

   Timing Cover Bolts18 Nm (14 lb-ft)
4. 4

   Inspect and remove timing chain tensioner
   Locate timing chain tensioner on front of engine block. Before removal, note tensioner position and extension. Remove tensioner mounting bolts and carefully extract tensioner assembly. Inspect tensioner for wear, scoring, or hydraulic fluid leakage. Check tensioner spring function. If replacing, compress new tensioner using bench vise and install retaining pin or clip to hold in compressed position until installation.
   ⚠Tensioner is spring-loaded. Control removal to prevent sudden movement.
   Torque spec

   Tensioner Bolt27 Nm (20 lb-ft)
5. 5

   Remove timing chain guides
   Remove timing chain guide mounting bolts from engine block. The 6.7L Cummins typically has upper and lower chain guides. Carefully extract guide assemblies, noting their orientation and position. Inspect guides for wear grooves, cracks, or material loss. Replace all guides as part of timing chain kit. Clean guide mounting surfaces on engine block.
   Torque spec

   Guide Bolts33 Nm (24 lb-ft)
6. 6

   Remove camshaft sprocket and timing chain
   Using camshaft holding wrench on the hex section of the camshaft, prevent cam rotation. Remove camshaft sprocket bolt. If equipped with cam phaser, remove cam phaser bolt instead. Carefully slide camshaft sprocket forward off camshaft dowel pin. Lift timing chain off crankshaft sprocket and remove chain from engine. Remove crankshaft sprocket if equipped, noting key or dowel pin orientation. Inspect crankshaft sprocket for wear or damage.
   ⚠Do not allow camshaft to rotate once sprocket is removed. This will affect valve timing and may cause piston-to-valve contact.
   Torque spec

   Camshaft Sprocket Bolt80 Nm (59 lb-ft)

   Cam Phaser Bolt65 Nm (48 lb-ft)
7. 7

   Inspect timing components and prepare for installation
   Thoroughly inspect crankshaft and camshaft sprocket mounting surfaces for damage, scoring, or wear. Check camshaft and crankshaft end play using dial indicator if available. Verify all new timing components are correct for application. Clean all timing chain contact surfaces with brake cleaner. Apply light coat of engine oil to new timing chain links. Verify new chain length matches old chain.
8. 8

   Install crankshaft sprocket and timing chain
   Install crankshaft sprocket onto crankshaft with any timing marks facing outward, ensuring key or dowel pin is properly seated. Rotate crankshaft to TDC if moved. Loop new timing chain around crankshaft sprocket, then route chain up and around camshaft position, maintaining slack on non-tensioned side. Verify timing marks on chain (if equipped with colored links) align with marks on sprockets per factory specification.
   ⚠️Incorrect timing mark alignment will result in engine damage. Triple-check alignment before proceeding.
9. 9

   Install camshaft sprocket
   Align camshaft sprocket with dowel pin on camshaft nose while maintaining timing chain position on sprocket teeth. Slide sprocket fully onto camshaft, ensuring dowel pin is fully engaged. Install camshaft sprocket bolt or cam phaser bolt finger-tight. Use camshaft holding wrench on hex to prevent rotation. Apply medium-strength threadlocker to bolt threads if installing cam phaser. Torque camshaft sprocket bolt to 80 Nm (59 lb-ft) or cam phaser bolt to 65 Nm (48 lb-ft) per specification.
   ℹ️Cam phaser bolt requires threadlocker application per factory specification.
   Torque spec

   Camshaft Sprocket Bolt80 Nm (59 lb-ft)

   Cam Phaser Bolt65 Nm (48 lb-ft)
10. 10

    Install timing chain guides
    Position new upper and lower timing chain guides in their respective locations on engine block. Ensure guides are oriented correctly with wear surfaces facing chain. Start all guide mounting bolts finger-tight, then torque timing chain guide bolts to 12 Nm (9 lb-ft) or general guide bolts to 33 Nm (24 lb-ft) depending on specific guide location. Verify guides do not interfere with chain movement.
    Torque spec

    Guide Bolts33 Nm (24 lb-ft)
11. 11

    Install timing chain tensioner
    Verify new tensioner is compressed and retaining pin or clip is installed. Position tensioner in mounting location on engine block. Install tensioner mounting bolts and torque to 25 Nm (18 lb-ft). After bolts are torqued, carefully remove tensioner retaining pin or clip to allow tensioner to apply pressure to timing chain. Verify tensioner extends smoothly and applies proper tension.
    ⚠Do not release tensioner until it is fully bolted in place. Premature release may cause chain to jump timing.
    Torque spec

    Tensioner Bolt27 Nm (20 lb-ft)
12. 12

    Verify timing alignment and rotate engine
    Install Cummins camshaft timing alignment tools per factory procedure to verify proper timing. With tools installed, crankshaft and camshaft should be locked in correct timing relationship. Remove alignment tools. Manually rotate crankshaft two complete revolutions clockwise (viewed from front). Reinstall alignment tools to verify timing marks still align correctly. If timing is off, disassemble and repeat timing chain installation.
    ⚠️If timing marks do not align after rotation, DO NOT proceed. Disassemble and correct timing before continuing.
13. 13

    Install new timing cover seals and gasket
    Install new crankshaft front seal into timing cover using seal installer tool. Ensure seal is driven squarely and seated to proper depth. Install new camshaft seal if equipped on timing cover. Apply thin bead of RTV silicone sealant to timing cover gasket or mating surface per factory specification (typically at parting lines between block and oil pan). Position new timing cover gasket on engine block, aligning all bolt holes.
    ℹ️RTV sealant must cure per manufacturer specifications. Some applications require wet installation, others require cure time before assembly.
14. 14

    Install timing cover and torque bolts
    Carefully position timing cover over crankshaft snout and onto engine block, ensuring gasket remains in position. Start all timing cover bolts finger-tight, identifying 6mm, 8mm, and 10mm bolt locations. Torque bolts in factory-specified sequence: 6mm bolts to 10 Nm (7 lb-ft), 8mm bolts to 25 Nm (18 lb-ft), and 10mm bolts to 45 Nm (33 lb-ft). If oil pump bolts are accessible, torque to 12 Nm (9 lb-ft).
    Torque spec

    Timing Cover Bolts18 Nm (14 lb-ft)

    Oil Pump Bolts12 Nm (9 lb-ft)
15. 15

    Install harmonic balancer and crankshaft pulley
    Clean crankshaft snout and harmonic balancer bore thoroughly. Apply light coat of engine oil to crankshaft snout. Slide harmonic balancer onto crankshaft, ensuring keyway or dowel pin is aligned. Install crankshaft pulley bolt with washer. Use crankshaft holding tool to prevent rotation. Torque crankshaft pulley bolt to 180 Nm (133 lb-ft). If bolt is TTY specification, follow manufacturer's torque-plus-angle procedure instead.
    ⚠Verify if crankshaft bolt is TTY (torque-to-yield) specification. TTY bolts require replacement and use torque-plus-angle tightening method.
    Torque spec

    Crankshaft Pulley Bolt180 Nm (133 lb-ft)

Reassembly

1. Install valve cover with new gasket. Torque valve cover bolts to 10 Nm (7 lb-ft) in proper sequence starting from center and working outward.
2. Lower engine back onto motor mounts and torque motor mount bolts to specification. Remove engine support fixture or hoist.
3. Reinstall all belt-driven accessories (power steering pump, A/C compressor, alternator) in reverse order of removal. Torque all mounting bolts to specification.
4. Reinstall radiator and A/C condenser assembly. Connect transmission cooler lines and tighten fittings.
5. Install radiator support brackets, fan shroud, and engine cooling fan assembly.
6. Connect upper and lower radiator hoses and coolant overflow tank.
7. Install new serpentine belt and verify proper routing and tension.
8. Reinstall hood and adjust alignment if necessary.
9. Install new engine oil filter and fill engine with 13 quarts of Mopar 5W-20 synthetic blend engine oil.
10. Refill cooling system with 18 quarts of Mopar OAT Purple coolant. Bleed air from cooling system per factory procedure.
11. Reinstall batteries and connect battery cables (positive first, then negative).
12. Replace fuel filter/water separator as part of this major service.

Verification

• Start engine and verify no oil or coolant leaks from timing cover, valve cover, or any disturbed connections. Check for proper oil pressure on gauge.
• Listen for any abnormal timing chain noise, rattling, or grinding sounds. Chain should operate quietly with proper tension.
• Allow engine to reach operating temperature and verify cooling fan operation and thermostat function.
• Check for proper engine idle quality and smooth acceleration. Any misfiring or rough running may indicate timing error.
• After initial test drive, recheck all timing cover bolts, accessory mounting bolts, and motor mount bolts for proper torque.
• Monitor engine oil level and coolant level after first heat cycle. Top off as needed.
• Scan for diagnostic trouble codes using scan tool. No timing-related codes should be present.
• After 500 miles, change engine oil and filter again to remove any break-in debris from new timing components.

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