Valve Springs - All

Complete replacement of all valve springs on the 5.9L Cummins I6 diesel engine, requiring removal of valve cover, rocker assembly, and use of valve spring compressor while maintaining valve train timing.

Warnings

Tools required

Parts

• Valve springs (set of 24) × 1 — Use OEM or high-performance specification
• Valve cover gasket × 1 — Use OEM specification
• Rocker lever assembly gasket × 1 — Use OEM specification
• Valve stem seals (set of 12) × 1 — Use OEM specification
• Valve keepers/locks (full set) × 1 — Use OEM specification

Fluids

• 15W-40 diesel oil or 5W-40 synthetic — 12 qt

Preparation

1. Ensure engine is completely cold to the touch (allow minimum 4 hours after last operation)
2. Disconnect both negative and positive battery cables to prevent accidental starter engagement
3. Remove engine cover and air intake system to access valve cover
4. Drain engine oil completely and remove oil filter
5. Remove intercooler tubes and any wiring harnesses that obstruct valve cover access
6. Clean entire valve cover area with brake cleaner to prevent debris from entering engine
7. Position drain pans to catch any residual oil
8. Prepare organized workspace with labeled containers for hardware from each cylinder

Procedure

1. 1

   Remove valve cover
   Remove all valve cover bolts in a crisscross pattern starting from the outside working inward. Carefully lift valve cover straight up to avoid damaging gasket surface. If cover is stuck, gently tap with rubber mallet - do not pry between sealing surfaces.
2. 2

   Inspect and document valve train
   Before disassembly, photograph or document the rocker arm orientation and pushrod positions. Check for any obvious wear patterns or damage. Verify all pushrods are properly seated in lifters by gently pressing down on each rocker arm.
3. 3

   Remove rocker lever assembly
   Loosen rocker shaft bolts gradually in multiple passes, working from the ends toward the center, approximately 1/4 turn at a time. This prevents warping the rocker shaft. Once all bolts are loose, remove bolts completely and lift entire rocker assembly off as a unit. Keep assembly together if reusing.
4. 4

   Remove pushrods
   Carefully remove all pushrods and place them in order in your parts organizer. Mark each pushrod's cylinder number and position (intake or exhaust). Inspect each pushrod for wear at ball ends and check for straightness by rolling on flat surface.
5. 5

   Prepare for valve spring removal
   Rotate engine to bring cylinder #1 to Top Dead Center (TDC) on compression stroke. Both valves should be fully closed with maximum clearance. Use compressed air adapter in the injector bore (if available) to pressurize cylinder and hold valves in place, or use alternate method of inserting clean rope through the injector bore to support valves.
6. 6

   Remove valve springs from cylinder #1
   Position valve spring compressor on first valve spring. Compress spring carefully until valve keepers are accessible. Use magnetic tool to remove both valve keepers. Slowly release spring compressor tension and remove spring retainer, spring, and valve stem seal. Place all components in labeled container for this cylinder. Repeat for second valve in cylinder #1.
   ⚠️Keep constant control of spring compressor. Sudden release can launch components causing injury.
7. 7

   Install new valve springs on cylinder #1
   Install new valve stem seal on valve guide using appropriate seal installation tool. Place new valve spring over valve stem (verify correct orientation - tighter coils toward cylinder head if spring is progressive rate). Position spring retainer. Compress new spring with compressor and install valve keepers in valve stem groove. Slowly release compressor and verify keepers are fully seated by gently tapping retainer with soft mallet.
8. 8

   Complete remaining cylinders
   Repeat steps 5-7 for each remaining cylinder in order (1-6). For each cylinder, rotate engine to bring that cylinder to TDC compression stroke before removing springs. Use air pressure or rope method via the injector bore to support valves during spring removal and installation. Maintain organization of old parts by cylinder for inspection.
9. 9

   Inspect all valve components
   Before reinstalling pushrods, inspect valve stem tips for wear or pitting. Check that all new valve springs are properly seated and keepers are locked in place by attempting to lift each retainer - it should not move. Verify no tools or debris remain in cylinder head.
10. 10

    Reinstall pushrods
    Apply light coat of assembly lube or engine oil to both ends of each pushrod. Reinstall each pushrod into its original position, ensuring ball end seats properly in lifter socket. Rotate engine slightly if needed to position lifters for easier pushrod installation.
11. 11

    Reinstall rocker lever assembly
    Apply clean engine oil to all rocker arm contact points and shaft. Position rocker assembly over pushrods, carefully aligning each rocker arm with its corresponding pushrod and valve stem. Install rocker shaft bolts finger-tight, then torque in multiple passes per the Cummins-specified sequence. Follow manufacturer's torque specifications - approximately 27 ft-lb (36 Nm) for rocker shaft pedestal bolts on the 5.9L Cummins ISB.
12. 12

    Perform valve lash adjustment
    With engine cold, adjust valve lash according to Cummins specifications (0.010" intake and 0.020" exhaust when cold, per the Cummins 5.9L ISB service manual). Use feeler gauge between rocker arm and valve crosshead. The engine firing order is 1-5-3-6-2-4. Adjust valves with corresponding cylinder at TDC compression stroke. Lock adjustment screw after setting.
13. 13

    Clean and prepare valve cover
    Thoroughly clean valve cover interior and all gasket surfaces on both cover and cylinder head using plastic scraper and brake cleaner. Ensure no old gasket material or debris remains. Check valve cover for warping or cracks. Install new valve cover gasket (dry - no sealant unless specified by gasket manufacturer).
14. 14

    Reinstall valve cover
    Position valve cover carefully onto cylinder head, aligning all bolt holes. Install all bolts finger-tight first. Torque valve cover bolts in crisscross pattern from center outward, typically to 18-20 ft-lb. Do not overtighten as this can distort cover and cause oil leaks.
15. 15

    Complete reassembly and refill fluids
    Reinstall all components removed during preparation: intercooler tubes, air intake, wiring harnesses, and engine cover. Install new oil filter and refill engine with approximately 12 quarts of appropriate diesel engine oil (15W-40 or 5W-40 synthetic), verifying level with the dipstick. Reconnect battery cables.

Reassembly

1. Double-check that all rocker shaft bolts are properly torqued
2. Verify all electrical connections and air intake components are fully secured
3. Ensure no tools or rags remain in engine compartment
4. Confirm oil drain plug is tight and new oil filter is properly installed

Verification

• Before starting engine, manually rotate engine through two complete revolutions by hand using breaker bar on crankshaft bolt to verify no valve-to-piston interference
• Check that engine rotates smoothly without binding or unusual resistance
• Start engine and listen for unusual valve train noise - ticking or clicking may indicate improper valve lash adjustment
• Allow engine to reach operating temperature and check for oil leaks around valve cover
• Verify oil pressure is normal (check gauge or warning light)
• After initial warm-up and cool-down, recheck valve cover bolt torque
• Recheck valve lash adjustment after first 500 miles and adjust if necessary

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