Freeze Plugs - All

Complete replacement of all engine block freeze plugs on the 5.9L Cummins diesel engine, requiring engine removal or significant disassembly to access all plugs.

Warnings

Tools required

Parts

• Freeze plug set (cup style expansion plugs) × 1 — Use OEM specification or Dorman 555-103
• Engine oil filter × 1 — Use OEM specification
• Fuel filter/water separator × 1 — Use OEM specification
• Radiator hoses (if damaged) × 1 — Use OEM specification
• Heater hoses (if damaged) × 1 — Use OEM specification
• Engine mount set × 1 — Inspect and replace if worn
• Gasket set (oil pan, front cover, thermostat housing) × 1 — Use OEM specification
• Serpentine belt × 1 — Use OEM specification
• Various clamps and hardware × 1 — Replace as needed

Fluids

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

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect both battery cables (negative first, then positive) and remove batteries
3. Drain engine coolant completely from radiator petcock and block drain plugs
4. Drain engine oil and remove oil filter
5. Remove hood for better access and label all bolts
6. Remove air intake system from turbocharger to air box
7. Relieve fuel system pressure and disconnect fuel lines from injection pump and fuel filter
8. Label and disconnect all electrical connectors from engine (alternator, starter, sensors, injectors, grid heater)
9. Disconnect exhaust system at turbocharger outlet
10. Remove radiator, intercooler, and associated hoses
11. Disconnect transmission from engine (either remove transmission or separate at bellhousing)
12. Place drip pans under vehicle to catch residual fluids
13. Take extensive photographs of all connections and routing for reference during reassembly

Procedure

1. 1

   Remove engine accessories and external components
   Remove serpentine belt, power steering pump (leave hoses attached and secure aside), A/C compressor (leave hoses attached and secure aside), alternator, fan and fan shroud, and any remaining brackets or accessories that would interfere with engine removal. Remove engine oil dipstick tube.
2. 2

   Disconnect transfer case and driveshafts
   For 4WD models, mark and disconnect front and rear driveshafts. Support transfer case with transmission jack if removing engine with transmission attached, or separate transfer case if removing engine only. Disconnect shift linkage and electrical connections from transmission.
3. 3

   Support and remove engine
   Attach engine hoist to the factory engine lifting eyes/brackets. Use load leveler for balance. Use load leveler for balance. Support transmission with transmission jack if separating. Remove engine mount bolts from frame brackets. Carefully lift engine, checking for any remaining connections. Tilt as needed to clear firewall and radiator support. Once clear, move engine to work area and mount on engine stand using bellhousing bolt holes.
4. 4

   Remove front engine components
   The 5.9L Cummins uses a gear-driven timing arrangement behind the front gear housing; verify whether any expansion plugs exist on the front of the block before removing the front cover/gear housing. If front-face plugs are present, remove harmonic balancer and front cover to access them, then clean all mating surfaces thoroughly.
5. 5

   Remove oil pan
   Remove all oil pan bolts and carefully separate oil pan from block using a gasket scraper or thin pry tool. Clean oil pan and block mating surfaces completely. This provides access to lower side freeze plugs.
6. 6

   Access rear freeze plugs
   Remove flywheel or flexplate by removing all mounting bolts. This exposes rear freeze plugs behind the flywheel housing area. On some plugs, the rear engine plate may need removal for better access.
7. 7

   Remove all freeze plugs
   Using freeze plug removal tool or slide hammer with appropriate attachment, carefully extract each freeze plug. Alternative method: use a punch to drive one side of plug inward, causing opposite side to tilt outward, then grip with pliers and remove. The 5.9L Cummins typically has 6-8 freeze plugs (exact count varies by block casting): sides of block, front, and rear. Inspect each bore carefully for corrosion, rust, or damage.
8. 8

   Prepare freeze plug bores
   Clean each freeze plug bore thoroughly with wire brush and abrasive pad. Remove all rust, scale, old sealant, and corrosion. Bores must be clean, smooth, and dry for proper plug seating. Use compressed air to blow out debris. Inspect for cracks or damage that might indicate deeper block problems.
9. 9

   Install new freeze plugs
   Apply thin coat of RTV silicone sealant around outer edge of each freeze plug (cup style). Position plug squarely in bore with cup side facing outward. Using appropriate size freeze plug driver and hammer, drive plug in until it seats flush with or slightly below block surface (typically 0.020-0.060 inch below surface). Ensure plug is driven in evenly without cocking. Work around all plug locations systematically.
10. 10

    Reinstall rear components
    Reinstall rear engine plate if removed. Clean flywheel/flexplate and crankshaft flange surfaces. Install flywheel or flexplate with new bolts if specified, torquing in star pattern per factory specifications. Apply thread locker to bolts as required.
11. 11

    Reinstall oil pan
    Apply new gasket or RTV silicone bead to oil pan rail per service manual specifications (typically 1/8 inch bead). Position oil pan carefully and install all bolts finger tight. Torque oil pan bolts in sequence from center outward to factory specification (verify exact values for the 5.9L Cummins — M8 pan bolts are typically ~18 ft-lbs, but larger/corner fasteners differ).
12. 12

    Reinstall front cover and timing components
    Install new front cover gasket or apply RTV as specified. Reinstall front cover and torque bolts to specification. Install harmonic balancer/damper with new bolt(s), torquing to factory specification for the 5.9L Cummins (verify exact torque and any angle-tightening requirement in the service manual). Reinstall any other front accessories removed.
13. 13

    Reinstall engine into vehicle
    Remove engine from stand and attach to engine hoist with load leveler. Carefully lower engine into engine bay, aligning with transmission bellhousing (if transmission remained in vehicle) or engine mounts. Tilt and maneuver as needed. Install engine mount bolts and torque to specification. Align and mate engine to transmission if separated, ensuring proper alignment. Install bellhousing bolts and torque to specification.
14. 14

    Reconnect all systems and accessories
    Reconnect transfer case and install driveshafts with alignment marks matched. Reinstall all accessories: alternator, A/C compressor, power steering pump. Install new serpentine belt. Reconnect all electrical connections per photos and labels. Reconnect fuel lines with new O-rings. Reconnect exhaust at turbocharger outlet with new gasket. Install new engine oil filter and dipstick tube.
15. 15

    Install cooling system and fill fluids
    Reinstall radiator, intercooler, fan shroud, and all coolant hoses with new clamps. Fill engine with specified diesel oil (approximately 12 quarts with filter — verify exact capacity). Fill cooling system with 50/50 HOAT coolant mixture (verify total system capacity for the 2007 Ram 3500 5.9L Cummins). Bleed cooling system per factory procedure. Check and fill all other fluids (transmission, transfer case, differentials, power steering) to proper levels.

Reassembly

1. Reinstall hood and align properly before final tightening
2. Reconnect both batteries (positive first, then negative)
3. Double-check all electrical connections, hoses, and hardware for proper installation
4. Verify all fluid levels are correct before starting engine
5. Ensure no tools or parts remain in engine bay

Verification

• Prime fuel system by cycling ignition without starting until injection pump is primed
• Start engine and immediately check for oil pressure on gauge
• Inspect all freeze plug locations for coolant leaks while engine is running
• Check for fuel, oil, and exhaust leaks at all connection points
• Allow engine to reach operating temperature and verify cooling system operation
• Check coolant level after engine cools and top off as needed
• Monitor for leaks over next several days of operation
• Verify proper engine temperature and no overheating conditions
• Test drive vehicle to verify normal operation and recheck all fluid levels
• Inspect engine bay after test drive for any new leaks or loose connections

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