Valve Spring - Single

This procedure covers the replacement of a single valve spring on the 5.9L Cummins diesel engine without removing the cylinder head, using compressed air to hold the valves in place.

Warnings

Tools required

Parts

• Valve spring (specify intake or exhaust) × 1 — Use OEM specification
• Valve keepers (locks) × 2 — Use OEM specification
• Valve cover gasket × 1 — Use OEM specification
• Valve stem seal (if damaged) × 1 — Use OEM specification

Preparation

1. Disconnect both negative battery cables and isolate them from the terminals
2. Allow engine to cool completely if recently operated
3. Identify which cylinder and valve (intake or exhaust) requires spring replacement
4. Remove the engine cover and air intake components as necessary for access
5. Remove the valve cover by removing all retaining bolts and carefully lifting off
6. Inspect the valve train and identify the affected valve location

Procedure

1. 1

   Position cylinder at TDC compression stroke
   Rotate the engine crankshaft using a socket on the crankshaft bolt until the piston for the affected cylinder is at Top Dead Center (TDC) on the compression stroke. Verify both intake and exhaust rocker arms are loose (valves closed). This is critical to ensure the valves are fully seated before spring removal.
2. 2

   Remove rocker arm assembly for affected valve
   Loosen and remove the rocker pedestal mounting bolts for the affected cylinder. Remove the rocker arm/pedestal assembly and pushrod. Keep components organized and note orientation for reinstallation. Keep these components organized and clean. Note the orientation of all parts for reinstallation.
3. 3

   Install compressed air adapter
   Thread the compressed air adapter into the injector bore for the affected cylinder (the fuel injector must be removed first). Note: the 5.9L Cummins does not have glow plugs; it uses a grid heater. Connect the air compressor line and pressurize the cylinder to approximately 90-100 PSI. This air pressure will hold the valves seated against their seats while the spring is removed. Listen for air leaks around valve seats; if significant leakage occurs, the valve may be damaged and head removal is recommended.
4. 4

   Compress valve spring and remove keepers
   Using the valve spring compressor tool, carefully compress the valve spring for the affected valve until the valve keepers (locks) are accessible. Use a magnetic pickup tool or small screwdriver to carefully remove both valve keepers from the valve stem groove. Keep the keepers in a safe location. Slowly release the spring compressor pressure while maintaining air pressure in the cylinder.
5. 5

   Remove valve spring and retainer
   With the keepers removed and spring compressor released, lift off the valve spring retainer and valve spring assembly. Inspect the valve stem seal; if it is damaged or shows signs of wear, replace it now. Remove the valve stem seal if replacement is necessary using a valve seal removal tool or pliers.
6. 6

   Inspect components and install new valve stem seal
   Inspect the valve stem for scoring, wear, or damage. Check the valve spring seat area on the cylinder head for debris or damage. If the valve stem seal was removed, install a new seal by carefully pressing it over the valve stem and onto the valve guide using a seal installation tool or appropriate sized socket. Lubricate the seal with clean engine oil.
7. 7

   Install new valve spring
   Install the new valve spring over the valve stem, ensuring proper orientation (closer-wound coils typically face the cylinder head). Install the valve spring retainer on top of the spring. Ensure all components are properly seated and aligned.
8. 8

   Compress spring and install valve keepers
   Using the valve spring compressor, compress the new valve spring until the valve stem keeper grooves are fully exposed above the retainer. Apply a small amount of grease to the valve keepers to help hold them in place. Carefully install both valve keepers into the valve stem groove, ensuring they are properly seated in the groove and the retainer. Slowly release the spring compressor while verifying the keepers remain seated. Once released, tap the valve stem tip gently with a plastic mallet to ensure keepers are fully seated.
9. 9

   Remove air pressure and verify valve operation
   Disconnect the air compressor line and remove the compressed air adapter from the injector bore. Reinstall the fuel injector using new sealing washers and torque to specification. Manually verify the valve moves freely by pressing down on the valve stem (it should spring back). Check that keepers are secure and properly seated.
10. 10

    Reinstall rocker arm assembly
    Reinstall the pushrod into its original location, ensuring it is properly seated in the lifter. Install the rocker pedestal and rocker arm in their correct positions. Install and hand-tighten the rocker arm pivot bolt. Adjust valve lash to Cummins service specification (0.010 in / 0.25 mm intake and 0.020 in / 0.51 mm exhaust) using a feeler gauge with the engine cold, setting each valve via the rocker adjusting screw and torquing the locknut to specification. Verify these values against current Cummins service documentation before proceeding. Tighten the rocker arm pivot bolt to specification after adjustment.

Reassembly

1. Clean the valve cover and cylinder head mating surfaces thoroughly, removing all old gasket material
2. Install a new valve cover gasket and reinstall the valve cover, tightening bolts in a cross-pattern sequence
3. Reinstall any air intake components and engine covers that were removed
4. Reconnect both negative battery cables

Verification

• Start the engine and listen for any unusual valve train noise, ticking, or tapping that might indicate improper keeper seating or incorrect valve adjustment
• Check for oil leaks around the valve cover gasket
• Verify engine runs smoothly at idle and under light acceleration
• Monitor engine for the first few minutes of operation to ensure proper valve train function
• Re-check valve lash after engine reaches operating temperature if specified by manufacturer

Related trouble codes on this vehicle

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

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