Engine Rebuild

Complete disassembly, inspection, machining, and rebuild of the 5.9L Cummins diesel engine including replacement of all wear components, seals, bearings, and gaskets.

Warnings

Tools required

Parts

• Complete engine overhaul gasket set × 1 — Use OEM specification
• Main bearing set (standard or appropriate oversize) × 1 — Use OEM specification
• Rod bearing set (standard or appropriate oversize) × 1 — Use OEM specification
• Piston and ring kit (set of 6) × 1 — Use OEM specification
• Camshaft bearing set × 1 — Use OEM specification
• Timing gear set (cam and crank gears) × 1 — Use OEM specification
• Main cap bolts (if stretch-type) × 12 — Use OEM specification
• Rod cap bolts (if stretch-type) × 12 — Use OEM specification
• Cylinder head bolts × 24 — Use OEM specification
• Valve stem seals × 12 — Use OEM specification
• Valve springs and retainers (if worn) × 12 — Use OEM specification
• Front crankshaft seal × 1 — Use OEM specification
• Rear crankshaft seal × 1 — Use OEM specification
• Oil pump × 1 — Use OEM specification
• Water pump × 1 — Use OEM specification
• Harmonic balancer (if damaged) × 1 — Use OEM specification
• Fuel injector o-rings and seals × 6 — Use OEM specification
• Thermostat × 1 — Use OEM specification
• Oil filter × 1 — Use OEM specification
• Fuel filter × 1 — Use OEM specification
• Engine oil pan bolts × 1 — Use OEM specification
• Valve cover gasket × 1 — Use OEM specification
• Intake manifold gaskets × 1 — Use OEM specification
• Exhaust manifold gaskets × 1 — Use OEM specification
• Thrust bearing set × 1 — Use OEM specification

Fluids

• 15W-40 diesel oil or 5W-40 synthetic — 12 qt
• HOAT coolant 50/50 — 28 qt

Preparation

1. Position vehicle on level surface with adequate overhead clearance for engine removal
2. Disconnect both batteries (negative terminals first) and remove batteries from vehicle
3. Drain engine oil completely and remove oil filter
4. Drain cooling system completely at block and radiator drain points
5. Remove hood and store in protected area
6. Relieve fuel system pressure by loosening fuel filter bleed screw
7. Label and photograph all electrical connections, vacuum lines, and hose routing
8. Have suitable clean workspace and parts storage prepared for disassembly
9. Obtain factory service manual for torque specifications and clearance tolerances
10. Arrange for machine shop inspection of block, crankshaft, camshaft, head, and cylinder boring/honing if needed

Procedure

1. 1

   Remove engine from vehicle
   Disconnect all electrical connectors including alternator, starter, injection pump, sensors, and chassis grounds. Disconnect fuel supply and return lines at injection pump and lift pump. Disconnect coolant hoses from thermostat housing, water pump, and heater connections. Remove intercooler tubes and charge air piping. Disconnect exhaust at turbocharger outlet. Remove transmission bell housing bolts and separate transmission from engine (may leave transmission in vehicle with proper support). Disconnect power steering pump and AC compressor, securing to frame without disconnecting lines. Attach engine hoist to the factory lifting eyes/brackets bolted to the cylinder head. Support engine weight and remove motor mounts. Carefully lift engine clear of frame rails and transmission input shaft. Transfer to engine stand mounted at bell housing bolt pattern.
2. 2

   External component removal
   Mount engine securely on stand. Remove turbocharger and all exhaust manifolds. Remove intake manifold and intercooler adapter plate. Remove the CP3 high-pressure fuel pump, fuel rail, high pressure fuel lines, and all six common-rail fuel injectors using the proper injector puller tool to avoid damaging bores. Remove alternator bracket, power steering pump bracket, and all accessory drive components. Remove water pump, thermostat housing, and coolant passages. Remove front gear cover, harmonic balancer using proper puller, and front cover. Remove valve cover and rocker assembly as complete unit with pedestals. Note rocker shaft orientation and mark pushrods for cylinder position.
3. 3

   Cylinder head removal and disassembly
   Remove cylinder head bolts in reverse of tightening sequence (inside-out pattern). Head bolts are torque-to-yield and must be replaced, not reused. Lift cylinder head straight up using proper lifting hooks to avoid damage to deck surface. Place head on clean protected surface. Remove all remaining valvetrain components including pushrods (keep in order), lifters (keep in order), and injector tubes. Using valve spring compressor, remove valve springs, retainers, and keepers. Extract all valves and keep organized by cylinder and position. Remove valve stem seals. Send cylinder head to machine shop for cleaning, inspection, crack testing, valve grinding, seat cutting, and deck surface milling if needed.
4. 4

   Oil pan and pickup removal
   Rotate engine on stand to access oil pan. Remove all oil pan bolts and carefully separate pan from block using plastic scrapers only. Remove oil pickup tube mounting bolts and extract pickup tube with screen. Inspect for debris or damage to screen. Remove oil pump from front of block by removing mounting bolts. Inspect oil pump drive gear for wear. Clean all gasket surfaces on block and pan thoroughly without gouging aluminum surfaces.
5. 5

   Piston and rod assembly removal
   Rotate engine to access crankshaft. Check for ridge at top of each cylinder bore. If ridge exists, use ridge reamer to remove before extracting pistons to prevent ring damage. Rotate crankshaft to position cylinder at bottom dead center. Mark connecting rod and cap with cylinder number and orientation before removal. Remove rod cap bolts (note if these are stretch bolts requiring replacement). Push piston and rod assembly up and out through top of cylinder bore, protecting crankshaft journal with rod bolt protectors or rubber hose over bolt threads. Keep rod caps with matching rods. Repeat for all six cylinders. Inspect each piston for cracks, ring groove wear, and skirt damage.
6. 6

   Crankshaft removal and inspection
   Mark main bearing caps with position and orientation before removal. Remove main cap bolts in sequence from outside to center. Main cap bolts are critical fasteners and must be replaced if stretch-type. Carefully remove main bearing caps keeping them in order. Check thrust bearing position (typically center main on this engine). Lift crankshaft straight up from block with assistance due to weight (verify weight; the forged crank is heavy and requires assistance). Inspect all journals with micrometer for out-of-round, taper, and undersize conditions. Check crankshaft for cracks using magnetic particle inspection. Measure main journal diameter and rod journal diameter at multiple points. Send crankshaft to machine shop for grinding if journals are worn beyond specification (typically 0.001 inch taper maximum).
7. 7

   Block disassembly and preparation
   Remove camshaft thrust plate bolts from front of block. Carefully slide camshaft forward and out of block, rotating as needed to clear cam bearings without scoring them. Inspect camshaft lobes for wear, pitting, or scoring. Measure lobe lift and compare to specifications. Drive out cam bearings using proper cam bearing tool, working from rear to front. Mark each piston for its cylinder number if not already marked. Using piston pin press or arbor press, remove piston pins from rods and separate pistons. Clean all pistons and remove old rings using ring expander tool. Remove all oil galley plugs for thorough cleaning. Clean block completely in hot tank or spray washer. Chase all threads with proper tap set. Send block to machine shop for magnaflux crack inspection, cylinder bore measurement, deck surface inspection, and line boring of main bearing saddles if needed. Have cylinders bored oversize and honed with proper crosshatch pattern if worn beyond specification.
8. 8

   Block measurement and machine work verification
   After machine shop work is complete, verify all machine work measurements. Using dial bore gauge, measure each cylinder at top, middle, and bottom in both thrust and pin directions to verify proper size and roundness (should be within 0.001 inch). Verify cylinder wall finish shows proper crosshatch pattern at 22-32 degree angle for ring sealing. Check deck surface flatness using precision straightedge and feeler gauges (should be within 0.005 inch maximum). Measure main bearing bore alignment and diameter. Install new cam bearings using proper driver, ensuring oil holes align with block passages. Install new oil galley plugs with sealant. Ensure all passages are clean and dry.
9. 9

   Piston and rod assembly
   Install new piston rings on pistons starting with oil control ring assembly (expander first, then rails), then lower compression ring (mark toward piston crown), then top compression ring (mark toward crown). Verify ring end gaps by placing each ring in cylinder bore and measuring with feeler gauge. File ring ends if gaps are too tight per specifications (typically 0.012-0.022 inch top ring, 0.010-0.020 inch second ring). Stagger ring gaps 120 degrees apart when installed. Heat piston pin bosses slightly if required and press piston pins into position, ensuring proper rod orientation (typically rod numbers face camshaft side). Install new rod bearings in rods and caps ensuring tang seats properly in rod notch. Lubricate bearings with assembly lube or fresh engine oil.
10. 10

    Crankshaft installation
    Install main bearing shells in block saddles and caps, ensuring tangs are properly seated. Install thrust bearing in proper location (verify in service manual). Lubricate all bearing surfaces generously with assembly lube. Carefully lower crankshaft into block, aligning with bearings. Install upper bearing shells if not already in place. Install main bearing caps in proper positions and orientation. Insert new main cap bolts and hand tighten. Follow proper torque sequence from center main outward in stages to final specification (verify factory spec in service manual — typically a stepped torque plus a final angle turn, NOT a single high torque value). Check crankshaft endplay with dial indicator while prying crank forward and back (specification typically 0.004-0.012 inch). Rotate crankshaft by hand to verify smooth rotation without binding.
11. 11

    Piston and rod installation
    Rotate crankshaft to position rod journal at bottom dead center for cylinder 1. Install ring compressor on piston, compressing all rings fully. Lubricate cylinder bore, piston, and rings with engine oil. Orient piston with mark toward front of engine. Insert rod bolt guides on rod bolts. Carefully tap piston into bore using wooden hammer handle, ensuring rings enter bore squarely without catching. Guide connecting rod onto crankshaft journal. Install rod cap in proper orientation matching marks. Install new rod bolts with light oil on threads and under head. Torque to specification in stages (verify factory spec in service manual — typically a low initial torque followed by a final angle turn). Repeat for all six cylinders. Verify each rod has proper side clearance on crankshaft journal with feeler gauge (typically 0.006-0.014 inch). Check bearing clearance with plastigage if new bearings are installed, verifying clearance is within specification (typically 0.0015-0.0035 inch).
12. 12

    Camshaft and timing gear installation
    Liberally coat all camshaft lobes and journals with camshaft assembly lube (not regular engine oil). Carefully slide camshaft into block, rotating slowly to avoid damaging cam bearings. Install camshaft thrust plate with bolts and torque to specification. Check camshaft endplay with dial indicator (typically 0.006-0.010 inch specification). Install crankshaft timing gear using press or proper driver if removed. Heat camshaft timing gear to expand bore slightly for easier installation. Install camshaft gear with timing marks aligned to crankshaft gear marks (marks together, gears meshed). Verify valve timing marks are properly indexed. Install new front cover seal in cover using proper seal driver. Apply RTV sealant to front cover gasket surface and install cover with new gasket. Torque cover bolts to specification in criss-cross pattern.
13. 13

    Oil system assembly
    Install new oil pump with proper gasket and torque mounting bolts to specification. Prime oil pump by filling with clean engine oil and rotating by hand. Install oil pickup tube with new o-ring seal, ensuring tube does not contact pan bottom (typically 1/4 to 3/8 inch clearance). Apply RTV sealant to oil pan rail and install new oil pan gasket. Position oil pan carefully and install all bolts hand tight. Torque oil pan bolts in sequence from center outward to specification (typically 18-24 ft-lbs). Allow RTV to cure for minimum time before adding oil.
14. 14

    Cylinder head assembly and installation
    After cylinder head returns from machine shop, install new valve stem seals on guides. Lubricate valve stems and install valves in proper positions. Install valve springs with closer-wound coils toward head. Compress springs and install keepers using valve spring compressor. Verify keepers are properly seated by tapping valve stem with plastic hammer. Check valve spring installed height and pressure if specifications are available. Install new injector tubes using proper driver. Clean head deck surface and block deck surface completely with solvent. Verify surfaces are clean and dry. Install new head gasket on block, ensuring all alignment dowels are in position and gasket orientation is correct. Carefully position cylinder head on block using lifting hooks. Install new cylinder head bolts with light oil on threads. Follow precise torque sequence provided in service manual, typically starting from center and working outward in specific pattern. Torque in multiple steps to final specification plus angle torque (verify factory spec in service manual — typically stepped torque values followed by a final 90-degree angle turn).
15. 15

    Valvetrain and external component installation
    Install lifters in their original bores with assembly lube. Install pushrods in proper positions with lubricant on ends. Position rocker shaft assembly on cylinder head with proper orientation. Torque rocker shaft pedestals to specification in sequence. Adjust valve lash to specification using the proper procedure for this Cummins engine (verify factory spec — commonly 0.010 in intake and 0.020 in exhaust cold; confirm exact values and valve-set positions in service manual). Install valve cover with new gasket and torque evenly. Install harmonic balancer using proper installer tool, not by hammering. Torque balancer bolt to specification. Install water pump with new gasket. Install the CP3 high-pressure fuel pump and fuel rail; no mechanical injection timing is required as injection timing is electronically controlled on this common-rail engine. Install fuel injectors with new o-rings and seals. Install turbocharger with new gaskets. Install all remaining external components including intake manifold, exhaust manifolds, alternator, and accessory brackets. Fill cooling system with the factory-specified coolant capacity of 50/50 HOAT coolant mixture (verify capacity in service manual — approximately 22-28 quarts total system). Install new oil filter and fill engine with the factory-specified oil capacity (approximately 12 quarts) of 15W-40 diesel oil or 5W-40 synthetic (verify capacity in service manual).
16. 16

    Engine installation and initial startup
    Attach engine hoist to lifting points and carefully lower engine into engine bay, aligning with transmission bell housing and motor mounts. Install transmission-to-engine bolts and torque to specification. Install motor mount bolts. Reconnect exhaust at turbocharger. Reconnect all coolant hoses, fuel lines, electrical connectors, intercooler piping, power steering pump, and AC compressor. Reconnect batteries (positive first, then negative). Prime fuel system by operating lift pump or cranking engine without starting until fuel pressure builds. Check for fuel leaks. Verify all connections are secure and no tools remain in engine compartment. Start engine and immediately verify oil pressure within 15 seconds. Allow engine to idle and monitor for leaks, unusual noises, or warning lights. Check coolant level after engine reaches operating temperature. Monitor engine temperature during initial run to verify proper cooling system operation.

Reassembly

1. Torque all fasteners to factory specifications using proper sequence and angle torque where specified
2. Use new gaskets and seals throughout - do not reuse head gasket, main cap bolts, or rod bolts if they are stretch-type
3. Verify all bearing clearances with plastigage before final assembly if using new bearings
4. Apply proper assembly lube to all bearing surfaces, camshaft lobes, and sliding surfaces during assembly
5. Ring end gaps must be staggered and verified in-bore before piston installation
6. Ensure all timing marks align correctly on camshaft and crankshaft gears
7. Prime oil pump and fuel system before initial startup attempt
8. Follow factory valve adjustment procedure for this solid lifter engine design

Verification

• Verify oil pressure reaches minimum 10 PSI at idle within 15 seconds of startup
• Check for fuel, oil, and coolant leaks throughout engine during initial run
• Verify engine idles smoothly without excessive noise, vibration, or misfiring
• Monitor engine temperature to confirm cooling system is functioning properly
• Check valve adjustment after initial heat cycle and readjust if necessary
• Verify no exhaust leaks at manifolds or turbocharger connections
• Change engine oil and filter after 500 mile break-in period
• Monitor oil consumption and performance during break-in (avoid heavy loads for first 1000 miles)
• Verify proper boost pressure under light acceleration to confirm turbocharger operation
• Recheck all critical bolt torques including head bolts, main caps, and rod caps after engine reaches operating temperature

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle