Main Bearings

Complete removal, inspection, and replacement of main bearing caps and inserts on the 8.0L V10 engine, requiring engine removal from vehicle and complete lower-end disassembly.

Warnings

Tools required

Parts

• Main bearing set (complete upper and lower shells, 5 journals) × 1 — Use OEM Mopar specification
• Thrust bearing set × 1 — Use OEM Mopar specification
• Main bearing cap bolts (TTY type) × 10 — Use OEM Mopar specification
• Oil pan gasket × 1 — Use OEM Mopar specification
• Rear main seal × 1 — Use OEM Mopar specification
• Oil pump pickup tube O-ring × 1 — Use OEM Mopar specification
• Engine oil filter × 1 — Use OEM Mopar specification
• Oil drain plug crush washer × 1 — Use OEM specification
• Coolant (ethylene glycol 50/50 mix) × 1 — Minimum 24 quarts total system capacity
• RTV silicone sealant (Mopar or equivalent) × 1 — Use OEM specification for oil pan corners
• Engine assembly lube × 1 — Moly-based assembly lube for bearings

Fluids

• 10W-30 conventional engine oil — 11 qt
• Ethylene glycol 50/50 coolant — 24 qt

Preparation

1. Park vehicle on level surface and engage parking brake. Place wheel chocks behind rear wheels.
2. Disconnect negative battery cable and secure away from battery post.
3. Allow engine to cool completely (minimum 2 hours after operation).
4. Drain engine oil completely and remove oil filter.
5. Drain cooling system at radiator petcock and block drain plugs.
6. Remove engine covers and air intake system completely.
7. Relieve fuel system pressure by removing fuel pump relay and cranking engine until it stalls.
8. Disconnect all fuel lines, electrical connectors, vacuum lines, and coolant hoses from engine. Label each connection for reassembly.
9. Remove exhaust manifolds and all exhaust system connections to engine.
10. Support transmission with transmission jack and remove bellhousing-to-engine bolts.
11. Remove starter motor.
12. Attach engine hoist to factory lifting points on engine. Verify load balance before unbolting motor mounts.
13. Prepare clean, well-lit workspace with engine stand ready for mounting engine once removed.

Procedure

1. 1

   Remove engine from vehicle
   With engine hoist attached and transmission supported, remove engine mount-to-frame bolts on both sides. Slowly lift engine while guiding it forward to clear transmission input shaft. Tilt engine as needed using load leveler to maintain clearance from firewall and radiator support. Once clear of vehicle, lower engine onto engine stand and secure using bellhousing bolt holes. Remove hoist.
2. 2

   Remove external accessories and front covers
   With engine on stand, remove alternator, power steering pump, A/C compressor (if equipped), water pump, thermostat housing, and all remaining brackets. Remove harmonic balancer using appropriate puller. Remove front timing cover and verify timing marks before proceeding. Note that this engine uses a distributorless ignition system (coil packs), not a conventional distributor. Remove valve covers.
3. 3

   Remove oil pan and oil pump
   Rotate engine stand to access bottom of engine. Remove all oil pan bolts (note any different length bolts for their locations). Carefully separate oil pan from block using plastic gasket scraper if necessary. Remove oil pump pickup tube bolts and remove pickup tube from oil pump. Remove oil pump mounting bolts and remove oil pump assembly from engine block. Note: Confirm the thrust bearing location against the factory service manual; the thrust bearing controls crankshaft endplay and its journal position must be verified for this engine.
   Torque spec

   Oil Pan Bolts12 Nm (9 lb-ft)

   Oil Pump Pickup Tube26 Nm (19 lb-ft)
4. 4

   Mark and document main bearing caps
   Before loosening any main bearing cap bolts, verify that all main bearing caps are already numbered from factory (typically 1-5 from front to rear). If not clearly marked, use permanent marker or metal stamps to number each cap on the side that faces the front of the engine. Note the orientation arrow or oil passage markings on each cap. Take photos for reference. The center main bearing (typically #3) houses the thrust bearing that controls crankshaft endplay.
5. 5

   Check crankshaft endplay before disassembly
   Mount dial indicator on block with plunger contacting crankshaft flange or thrust surface. Use pry bar to move crankshaft fully forward, zero dial indicator, then pry crankshaft fully rearward and record endplay reading. Verify crankshaft endplay against the factory service manual specification for this engine (confirm exact range before proceeding). Excessive endplay indicates worn thrust bearings. This baseline measurement is critical for comparison after bearing replacement.
6. 6

   Remove connecting rod caps and push pistons up
   Rotate crankshaft to access each connecting rod cap. Verify rod caps are numbered matching their cylinder and orientation. Loosen and remove connecting rod cap bolts for all 10 cylinders. Remove rod caps and store with their bolts. Push each piston/rod assembly up into its cylinder bore to clear crankshaft journals. Install short lengths of rubber hose over rod bolts to protect crankshaft journals during crankshaft removal.
7. 7

   Remove main bearing cap bolts
   Working from the outer caps toward the center, gradually loosen all main bearing cap bolts in stages (1/4 turn each, alternating sides) to prevent binding. Verify the exact number of main bearing caps and bolts per cap against the factory service manual before removal, as main bolt count is critical for ordering new TTY bolts. Once all bolts are loose, remove all main bearing cap bolts completely and store them separately (they must be replaced with new TTY bolts).
8. 8

   Remove main bearing caps
   Carefully remove each main bearing cap in order, starting from the outer caps (#1 and #5) and working toward center. Caps may be tight; tap gently with dead blow hammer on cast bosses only (never on machined surfaces) or use main cap puller if available. As each cap is removed, remove lower bearing shell and store it with its cap. Keep all caps in order with their bearing shells.
9. 9

   Remove crankshaft from engine block
   With all main caps removed, carefully lift crankshaft straight up and out of engine block. This is a heavy component (approximately 60-70 lbs); have assistance available. Place crankshaft on clean work surface padded with shop rags to prevent damage to journals. Remove upper main bearing shells from block, noting which journal each came from. Remove thrust bearing halves from center main journal (both upper in block and lower from cap #3).
10. 10

    Inspect crankshaft journals and block saddles
    Clean all crankshaft main journals thoroughly with solvent and lint-free cloth. Inspect each journal for scoring, discoloration, or wear. Measure each main journal diameter with outside micrometer in multiple locations and directions; compare against the factory service manual standard diameter specification for this engine. Use dial bore gauge to measure main bearing saddle bores in block with caps torqued (using old bolts for measurement only). Any out-of-round condition beyond 0.001 inch or taper beyond 0.0005 inch requires machine shop services. Check oil passages in block and crankshaft for blockages.
11. 11

    Clean all bearing surfaces and oil passages
    Thoroughly clean all main bearing saddles in block and caps using non-metallic scraper and solvent. Remove all old bearing material, dirt, or debris. Clean all oil passages in block using rifle brush and compressed air, blowing from inside passages outward. Verify oil passages are clear by running clean solvent through them. Wipe all surfaces with clean, lint-free cloth. Inspect bearing cap mating surfaces for fretting, damage, or irregularities.
12. 12

    Install upper main bearing shells in block
    Ensure block bearing saddles are completely clean and dry. Install new upper main bearing shells in block, ensuring bearing tang engages notch in saddle. Do NOT use any oil or assembly lube yet. Install thrust bearing halves on center main journal (#3) with oil grooves facing outward. Verify each bearing is fully seated with no gaps between bearing back and saddle. Each bearing should snap into place with light pressure.
13. 13

    Install lower main bearing shells in caps
    Install new lower main bearing shells in each main bearing cap, ensuring bearing tang engages notch in cap. Match thrust bearing halves to cap #3 with oil grooves facing outward. Verify each bearing is fully seated. Do NOT apply oil or assembly lube yet. Keep caps organized in order.
14. 14

    Verify bearing clearances with Plastigage
    Place strip of Plastigage across each main journal on crankshaft (across the full width but not over oil holes). Carefully lower crankshaft into block, seating it into bearing shells. Install main bearing caps in correct order and orientation WITHOUT applying any oil. Install old main bearing cap bolts finger-tight, then torque in sequence to the initial torque value specified in the factory service manual for this engine (typically from center outward). Do NOT rotate crankshaft with Plastigage in place. Remove each cap carefully and measure crushed Plastigage width using scale on Plastigage envelope. Compare measured clearance against the factory service manual specification for main bearing oil clearance on this engine. Record clearances for all 5 journals.
15. 15

    Remove Plastigage and prepare for final assembly
    Remove crankshaft from block again. Remove all Plastigage residue from crankshaft journals and bearing surfaces using clean cloth. Clean both upper and lower bearing surfaces one final time to remove any contamination. Verify all surfaces are spotlessly clean.
16. 16

    Lubricate bearings and install crankshaft
    Apply generous coat of moly-based engine assembly lube to all upper bearing shells in block and to all crankshaft main journals. Carefully lower crankshaft into block, seating each journal into its bearing. Apply assembly lube to all lower bearing shells in caps. Verify crankshaft rotates freely by hand before installing caps.
17. 17

    Install main bearing caps with new bolts
    Install main bearing caps in correct order (#1-#5) and orientation, ensuring alignment dowels (if equipped) are engaged. Install NEW main bearing cap bolts (TTY type) and hand-tighten all bolts. Following factory tightening sequence (typically center main first, then alternating outward), torque all main bearing cap bolts to the base torque value specified in the factory service manual. Then apply the additional angle-torque specified in the FSM for this engine. Use torque angle gauge for accuracy. Verify crankshaft still rotates freely after torquing.
    Torque spec

    Main Bearing Cap Bolts115 Nm (85 lb-ft)
18. 18

    Verify crankshaft endplay after assembly
    Mount dial indicator on block with plunger against crankshaft thrust surface. Pry crankshaft fully forward, zero indicator, then pry fully rearward and record endplay. Compare endplay against the factory service manual specification for this engine. If endplay is incorrect, verify thrust bearing installation and check for bearing or crankshaft damage.
19. 19

    Install connecting rod assemblies
    Rotate crankshaft to position each rod journal at bottom dead center. Remove rubber hoses from rod bolts. Lubricate rod bearings and journals with assembly lube. Guide each piston/rod assembly down into its bore, ensuring ring gaps are properly positioned. Install rod caps in correct orientation and torque rod cap bolts to the specification listed in the factory service manual for this engine. Repeat for all 10 cylinders. Verify crankshaft rotates smoothly by hand.
20. 20

    Install rear main seal
    Clean rear main seal housing in block and on crankshaft seal surface. Install new rear main seal using appropriate seal driver or seal installation tool, driving seal in squarely until flush with housing. Apply small amount of RTV to corners where seal housing meets block if specified by service manual. Coat seal lip with clean engine oil.
21. 21

    Install oil pump and pickup tube
    Prime oil pump by filling with clean engine oil and rotating pump gears by hand. Install oil pump onto engine block with new O-ring or gasket, engaging the oil pump drive per this engine's configuration (this engine has no distributor). Install and torque oil pump mounting bolts to the FSM specification. Install oil pump pickup tube with new O-ring, positioning tube properly in oil pump. Torque pickup tube mounting bolts to the factory service manual specification.
    Torque spec

    Mounting Bolts27 Nm (20 lb-ft)

    Oil Pump Pickup Tube26 Nm (19 lb-ft)
22. 22

    Install oil pan
    Clean oil pan and block mating surfaces thoroughly. Apply thin bead of RTV silicone at corners where front cover meets block and where rear main seal housing meets block. Install new oil pan gasket. Position oil pan and install all oil pan bolts finger-tight. Following specified tightening sequence (typically starting at center and working outward in spiral pattern), torque oil pan bolts to the factory service manual specification for this engine. Allow RTV to cure per manufacturer instructions before filling with oil.
    Torque spec

    Oil Pan Bolts12 Nm (9 lb-ft)
23. 23

    Complete engine assembly
    Install timing cover with new gasket, ensuring proper seal around crankshaft. Install harmonic balancer to crankshaft, torquing center bolt to specification. Reinstall water pump, thermostat housing, and all external accessories (alternator, power steering pump, A/C compressor) with proper belt routing. Install valve covers with new gaskets. Install distributor in noted position, ensuring proper gear engagement.
24. 24

    Reinstall engine in vehicle
    Remove engine from stand and attach to engine hoist with load leveler. Carefully lower engine into engine bay, aligning with transmission input shaft. Guide engine into position, tilting as necessary to clear firewall and radiator support. Align engine mounts and install mount bolts. Torque engine-to-transmission bellhousing bolts to the factory service manual specification in the specified sequence. Remove engine hoist.
    Torque spec

    Transmission-to-Engine Bolts68 Nm (50 lb-ft)
25. 25

    Reconnect all systems and refill fluids
    Reinstall starter motor. Reconnect all electrical connectors, vacuum lines, fuel lines, and coolant hoses using labels for reference. Install exhaust manifolds with new gaskets. Reconnect exhaust system. Install new oil filter. Install oil drain plug with new crush washer and torque to the factory service manual specification. Fill engine with the FSM-specified quantity and grade of engine oil (confirm capacity and viscosity for this engine before filling). Refill cooling system with 50/50 conventional (green) ethylene glycol coolant mix per the total system capacity specified in the factory service manual. Reconnect negative battery cable.
    Torque spec

    Oil Drain Plug35 Nm (26 lb-ft)

Reassembly

1. Engine reassembly mirrors disassembly in reverse order with these critical points: ALL main bearing cap bolts must be NEW (TTY type); bearing clearances MUST be verified before final assembly; apply moly-based assembly lube to all bearing surfaces; follow torque sequences exactly as specified; allow RTV sealant to cure before adding fluids.
2. Prime oiling system before first start by removing distributor or fuel pump relay and cranking engine until oil pressure gauge shows pressure (typically 10-15 seconds).
3. On first start, monitor oil pressure immediately and listen for any abnormal noises. Oil pressure should register within 3-5 seconds.
4. Run engine at varying RPM (1500-2500) for 20 minutes to allow rings to seat and bearings to mate properly. Monitor for leaks, unusual noises, or overheating.

Verification

• Check for oil leaks around oil pan, rear main seal, and oil pump after initial run-in period.
• Verify proper oil pressure: minimum 6 psi at idle when hot, 25-80 psi at 3000 RPM.
• Check for coolant leaks at all connection points.
• Listen for any knocking, ticking, or abnormal engine noises that could indicate bearing problems.
• After 500 miles, change oil and filter and inspect oil for bearing material or metallic particles.
• Monitor oil pressure and consumption over first 1000 miles to verify bearing wear is within normal parameters.

More procedures for this vehicle