Replace the timing chain guide on a 6.7L Cummins diesel engine by removing the front timing cover, inspecting and replacing worn guide components, and reassembling with proper torque specifications.

Warnings

Tools required

Parts

• Timing chain guide × 1 — Use OEM specification
• Timing cover gasket × 1 — Use OEM specification
• Front crankshaft seal × 1 — Use OEM specification
• Valve cover gasket × 1 — Use OEM specification
• Timing chain tensioner (if worn) × 1 — Use OEM specification
• Timing chain guide bolts × 1 — Use OEM specification
• Permatex Ultra Grey RTV sealant × 1 — 81878

Fluids

• Mopar OAT Coolant (Purple) — 2 qt
• Mopar 5W-20 Synthetic Blend — 1 qt

Preparation

1. Disconnect both battery negative cables and wait 5 minutes for system capacitors to discharge
2. Drain engine coolant into appropriate container from lower radiator hose and block drain
3. Remove engine cover and air intake system from turbocharger inlet to air filter housing
4. Remove serpentine drive belt and fan shroud assembly
5. Remove radiator upper support bracket and carefully tilt radiator forward for access
6. Position engine support fixture across engine compartment and attach lifting chains to engine lift points
7. Raise and support vehicle on jack stands, remove front skid plate if equipped
8. Drain approximately 1 quart of engine oil to prevent spillage during timing cover removal

Procedure

1. 1

   Remove crankshaft pulley and damper
   Remove the seven bolts securing the vibration damper to the crankshaft pulley. Use crankshaft holding tool to prevent rotation and remove the crankshaft pulley center bolt. Remove pulley and damper assembly from crankshaft. Inspect keyway for damage.
   Torque spec

   Crankshaft Pulley Bolt238 Nm (176 lb-ft)
2. 2

   Remove valve cover and upper accessories
   Disconnect fuel injector harness connectors and set aside. Remove valve cover bolts in reverse of tightening sequence and carefully lift valve cover off. Remove any remaining accessories blocking access to timing cover including power steering pump (support aside without disconnecting lines), AC compressor mounting bolts (support aside), and alternator mounting.
   Torque spec

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

   Remove front motor mount
   Support engine weight with engine support fixture. Remove front motor mount through-bolt and mounting bracket bolts. Raise engine approximately 2 inches to provide clearance for timing cover removal. Ensure engine is stable and all support points are secure before proceeding.
   ⚠️Verify engine support fixture is securely attached and capable of supporting engine weight before removing motor mount.
4. 4

   Remove timing cover
   Remove all timing cover bolts, noting the different lengths and locations (8mm bolts are longer and located at specific positions). Carefully separate timing cover from engine block using plastic pry points. Do not pry on sealing surfaces. Remove front crankshaft seal from timing cover. Clean all RTV sealant from mating surfaces on block and timing cover using gasket scraper.
   Torque spec

   Timing Cover Bolts18 Nm (14 lb-ft)
5. 5

   Verify timing marks and document position
   Rotate crankshaft to TDC position for cylinder #1 (compression stroke). Verify timing marks on camshaft sprocket and crankshaft sprocket are aligned with marks on engine block. Use paint marker or take photographs to document exact chain position on sprockets before removal. Count and mark chain links between timing marks for reference during reassembly.
   ⚠Take detailed photographs and notes of timing mark positions. Incorrect reassembly will cause catastrophic engine damage.
6. 6

   Remove timing chain tensioner
   Remove tensioner bolt and carefully extract timing chain tensioner assembly. Note the position and orientation of tensioner. Inspect tensioner for wear, scoring, or damage. If tensioner shows wear or has more than 0.5 inches of travel used, replace with new unit.
   Torque spec

   Tensioner Bolt27 Nm (20 lb-ft)
7. 7

   Remove timing chain and inspect sprockets
   Remove camshaft sprocket bolt while preventing camshaft rotation (use appropriate holding tool on camshaft hex). Slide camshaft sprocket and timing chain off together as an assembly. Remove chain from crankshaft sprocket. Inspect both sprockets for wear, chips, or damage to teeth. Replace if any wear is evident.
   ⚠Do not allow camshaft or crankshaft to rotate independently with chain removed. Mark positions before removal.
   Torque spec

   Camshaft Sprocket Bolt101 Nm (74 lb-ft)
8. 8

   Remove and replace timing chain guide
   Remove timing chain guide bolts securing the guide to the engine block. If guide uses different bolt sizes, note their specific locations. Carefully remove worn timing chain guide. Clean mounting surface thoroughly. Install new timing chain guide and secure with new bolts (if specified as replace if worn). Torque guide bolts to specification in a cross-pattern if multiple bolts are used.
   Torque spec

   Guide Bolts33 Nm (24 lb-ft)
9. 9

   Install timing chain and sprockets
   Verify crankshaft is still at TDC position. Install timing chain onto crankshaft sprocket. Route chain over new guide and install camshaft sprocket with chain engaged, aligning timing marks exactly as documented during disassembly. Install camshaft sprocket bolt finger-tight. Double-check all timing marks are properly aligned before proceeding.
   ⚠Verify timing marks multiple times before torquing components. Even one tooth off will cause engine damage.
10. 10

    Install tensioner and torque camshaft sprocket
    Install timing chain tensioner and torque tensioner bolt to specification. Verify tensioner has engaged chain properly and chain has correct tension. Hold camshaft with appropriate tool and torque camshaft sprocket bolt to specification. Manually rotate engine two complete revolutions and verify all timing marks return to proper alignment.
    Torque spec

    Camshaft Sprocket Bolt101 Nm (74 lb-ft)

    Tensioner Bolt27 Nm (20 lb-ft)
11. 11

    Install timing cover with new gasket and seal
    Install new front crankshaft seal into timing cover using seal driver. Apply thin bead of RTV sealant to timing cover at cylinder head to engine block junction points as specified in service manual. Install new timing cover gasket. Position timing cover onto engine and install all bolts finger-tight. Torque 8mm timing cover bolts first in specified sequence, then torque remaining bolts to specification.
    Torque spec

    Timing Cover Bolts18 Nm (14 lb-ft)
12. 12

    Reinstall crankshaft pulley and accessories
    Clean crankshaft snout and pulley bore. Install vibration damper and crankshaft pulley assembly onto crankshaft, ensuring keyway is properly aligned. Install and hand-tighten crankshaft pulley bolt. Use holding tool and torque crankshaft pulley bolt to specification. Reinstall all accessories removed earlier including alternator, AC compressor, and power steering pump.
    Torque spec

    Crankshaft Pulley Bolt238 Nm (176 lb-ft)
13. 13

    Install valve cover and complete reassembly
    Install new valve cover gasket. Clean valve cover mating surface. Position valve cover and install bolts finger-tight. Torque valve cover bolts in proper sequence from center outward to specification. Reconnect fuel injector harness connectors. Lower engine onto motor mount, install motor mount bracket and through-bolt, then remove engine support fixture.
    Torque spec

    Valve Cover Bolts10 Nm (7 lb-ft)

Reassembly

1. Reinstall front skid plate if equipped and lower vehicle from jack stands
2. Reinstall radiator support bracket and position radiator properly
3. Install fan shroud assembly and serpentine drive belt with proper tension
4. Reinstall air intake system from air filter housing to turbocharger inlet
5. Refill cooling system with Mopar OAT Purple coolant to proper level and bleed air from system
6. Verify engine oil level and add oil as needed to bring to full mark on dipstick
7. Reconnect battery negative cables
8. Install engine cover

Verification

• Start engine and verify no coolant, oil, or air leaks from timing cover area
• Listen for abnormal timing chain noise during idle and light acceleration
• Monitor engine temperature during warm-up cycle to verify proper cooling system operation
• Perform test drive and verify normal engine operation under load with no unusual noises
• Re-check all fluid levels after test drive and inspect timing cover area for any seepage
• Scan for diagnostic trouble codes and verify no timing-related codes are present
• After 50-100 miles of operation, re-torque valve cover bolts and inspect for oil leaks

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