Complete removal and replacement of main bearings on the 6.7L Cummins diesel engine, requiring engine removal from the vehicle and crankshaft extraction.

Warnings

Tools required

Parts

• Main bearing set (standard or appropriate undersize) × 1 — Use OEM specification
• Thrust bearing set × 1 — Use OEM specification
• Main cap bolts (torque-to-yield, must replace) × 14 — Use OEM specification
• Oil pan gasket × 1 — Use OEM specification
• Front crankshaft seal × 1 — Use OEM specification
• Rear crankshaft seal × 1 — Use OEM specification
• Oil pump gasket/O-rings × 1 — Use OEM specification
• Engine oil filter × 1 — Use OEM specification
• Coolant × 1 — Mopar OAT Purple
• Engine oil × 1 — Mopar 5W-20 Synthetic Blend

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
2. Disconnect both battery cables, negative first
3. Drain engine oil completely and remove oil filter
4. Drain cooling system completely into appropriate container
5. Remove hood and store in safe location
6. Remove intercooler piping and charge air cooler
7. Disconnect all electrical connectors from engine (mark for reinstallation)
8. Disconnect fuel lines at fuel filter housing and cap all openings
9. Remove exhaust downpipe and turbocharger if necessary for clearance
10. Remove radiator, fan assembly, and all cooling hoses
11. Disconnect transmission from engine (leave in vehicle with transmission jack support)
12. Remove transfer case to transmission connection
13. Disconnect power steering lines if equipped
14. Remove engine-to-chassis ground straps
15. Attach engine hoist to factory lifting points on cylinder head

Procedure

1. 1

   Remove engine from vehicle
   Support transmission with transmission jack. Remove engine mount bolts from both sides. Carefully raise engine while guiding away from transmission input shaft. Lift engine clear of vehicle and transfer to engine stand. Secure engine to stand using bell housing bolt holes.
   Torque spec

   Mounting Bolts37 Nm (27 lb-ft)
2. 2

   Remove external engine components
   With engine on stand, remove alternator, A/C compressor, power steering pump (if not already removed), oil filter housing, fuel filter housing, and all remaining external accessories. Remove valve cover(s). Remove front engine cover and timing components including gear train or timing chain as applicable to access front main seal area.
   Torque spec

   Cover Bolts22 Nm (16 lb-ft)
3. 3

   Remove oil pan and oil pump
   Remove all oil pan bolts and carefully separate pan from block (may require light tapping with rubber mallet). Remove oil pickup tube. Remove oil pump mounting bolts and extract oil pump assembly. Clean all gasket surfaces thoroughly.
   Torque spec

   Gasket Bolts27 Nm (20 lb-ft)
4. 4

   Mark and inspect main bearing caps
   Using a permanent marker or punch, clearly mark each main bearing cap with its number (1-7, front to back) and orientation arrow pointing toward front of engine. Verify caps are already marked from factory. Inspect cap surfaces for any damage or irregularities. Take photos for reference.
   ⚠Main caps MUST be reinstalled in exact original position and orientation. Mixing caps will cause immediate bearing failure.
5. 5

   Remove main bearing caps
   Remove all main cap bolts in reverse order of tightening (work from ends toward center). Carefully remove each main cap using appropriate pry points or cap puller. Keep caps in order and store with their respective bolts (which will be discarded). Note the location of thrust bearing (typically center main). Remove upper and lower bearing shells from each cap and saddle, keeping them with their respective positions.
   ⚠Do not pry against machined bearing surfaces. Use only designated pry points or cap removal tool.
   Torque spec

   Main Cap Bolts60 Nm (44 lb-ft) + 90°
6. 6

   Remove crankshaft
   With assistance or lifting equipment, carefully lift crankshaft straight up and out of engine block. Place on clean, padded surface. Remove thrust bearing halves from block if they did not come out with crankshaft. Inspect crankshaft journals for scoring, heat discoloration, or damage.
   ⚠Crankshaft weighs approximately 120 lbs. Use proper lifting technique and assistance.
7. 7

   Measure and inspect crankshaft journals
   Using micrometers, measure all main bearing journals in multiple locations (front-to-back and side-to-side) to check for taper and out-of-round conditions. Standard journal diameter is 3.2677-3.2685 inches. Maximum taper is 0.001 inch, maximum out-of-round is 0.0005 inch. Record all measurements. If journals are out of specification, crankshaft must be ground to next undersize (0.010, 0.020, or 0.030 inch).
   ℹ️Any scoring, heat discoloration, or measurements beyond specification require crankshaft machining or replacement.
8. 8

   Inspect block bearing saddles
   Thoroughly clean all bearing saddles in block using solvent and lint-free rags. Inspect for scoring, damage, or wear. Use telescoping bore gauge to measure bearing saddle bore diameter with caps installed (using new bolts torqued to specification). Verify saddle alignment and condition.
   ⚠Any damage to bearing saddles may require line boring or block replacement. Do not proceed with damaged saddles.
9. 9

   Install new bearing shells
   Ensure all bearing surfaces are perfectly clean and dry. Install new upper bearing shells into block saddles, ensuring bearing tang engages slot in saddle. Apply light coat of assembly lubricant to bearing surfaces. Install lower bearing shells into main caps with tang properly engaged. For thrust bearing location (typically #4 main), ensure thrust bearing halves are correctly positioned.
   ℹ️Do not use excessive lubricant. Bearings should be lightly coated, not dripping wet.
10. 10

    Install crankshaft and check bearing clearance
    Carefully lower crankshaft into block, seating it in bearing saddles. Place Plastigage strips on each crankshaft journal (do not rotate crankshaft after placing Plastigage). Install main caps in correct positions with NEW bolts. Torque main cap bolts to 44 lb-ft, then rotate additional 90 degrees following proper sequence (center main first, then alternating outward). Remove caps and measure Plastigage width. Specified clearance is 0.0012-0.0042 inches. If clearance is incorrect, verify bearing size and journal dimensions.
    ⚠️Never reuse torque-to-yield main cap bolts. Always install new bolts.
    ⚠Do not rotate crankshaft with Plastigage in place. This will give false readings.
    Torque spec

    Main Cap Bolts60 Nm (44 lb-ft) + 90°
11. 11

    Perform final main bearing installation
    Once bearing clearances are verified, remove all caps again. Apply assembly lubricant to all bearing surfaces and crankshaft journals. Install crankshaft for final time. Install all main caps in correct positions with NEW bolts. Torque main cap bolts following proper sequence: Start with center main cap (#4), torque to 44 lb-ft, then rotate 90 degrees. Move to adjacent caps (#3 and #5), then continue outward alternating pattern. Verify crankshaft rotates freely by hand with no binding or tight spots.
    ⚠If crankshaft does not rotate freely after torquing, do not force. Disassemble and inspect for incorrect bearing installation or debris.
    Torque spec

    Main Cap Bolts60 Nm (44 lb-ft) + 90°
12. 12

    Check crankshaft endplay
    Using dial indicator or feeler gauge, check crankshaft endplay at thrust bearing location. Pry crankshaft fully forward, zero indicator, then pry fully rearward and note reading. Specification is 0.0020-0.0086 inches. If endplay is incorrect, verify thrust bearing installation and condition.
    ℹ️Excessive endplay will cause main bearing failure. Insufficient endplay will cause thrust bearing failure.
13. 13

    Reinstall oil pump and oil pan
    Install oil pump with new gasket/O-rings. Install oil pickup tube ensuring proper seating. Apply thin bead of RTV sealant if specified or install new oil pan gasket according to manufacturer instructions. Install oil pan and torque gasket bolts to specification in criss-cross pattern from center outward. Allow RTV to cure per manufacturer specification before filling with oil.
    ℹ️Follow exact RTV cure time before adding oil or starting engine to prevent leaks.
    Torque spec

    Gasket Bolts27 Nm (20 lb-ft)

    Mounting Bolts37 Nm (27 lb-ft)
14. 14

    Reinstall timing components and front cover
    Install new front crankshaft seal. Reinstall timing gears/chain, ensuring proper alignment marks. Install front cover with new gasket/RTV as applicable. Reinstall all external accessories including alternator, A/C compressor, power steering pump, and belt-driven components. Torque all fasteners to specification.
    Torque spec

    Cover Bolts22 Nm (16 lb-ft)

    Sensor Bolts15 Nm (11 lb-ft)
15. 15

    Reinstall engine in vehicle
    Remove engine from stand and attach to engine hoist. Carefully lower engine into vehicle while aligning with transmission input shaft. Install engine mount bolts and torque to specification. Reconnect transmission to engine. Reconnect all electrical connectors, fuel lines, cooling hoses, exhaust components, and remaining components in reverse order of removal. Install new oil filter. Refill with specified engine oil and coolant. Reinstall hood.
    Torque spec

    Mounting Bolts37 Nm (27 lb-ft)

Reassembly

1. Double-check all electrical connectors are properly seated
2. Verify all fluid levels (oil, coolant, power steering) are correct
3. Ensure no tools or parts remain in engine compartment
4. Verify all hose clamps and fasteners are tight
5. Reconnect battery cables (positive first, then negative)

Verification

• Prime oil system by cranking engine with fuel system disabled until oil pressure registers
• Start engine and immediately verify oil pressure reaches normal range (10+ PSI at idle)
• Check for oil leaks at pan gasket, front seal, and all external seals
• Check for coolant leaks at all connections
• Listen for abnormal noises (knocking, rattling) that would indicate bearing issues
• Allow engine to reach operating temperature and verify proper cooling system operation
• Monitor oil pressure during warm-up and after reaching operating temperature
• Perform test drive and monitor for vibrations or unusual noises under load
• Re-check all fluid levels after test drive and inspect for leaks
• After 500 miles, change engine oil and filter, inspect for metal particles in oil

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