Lifter - Single

Replacement of a single valve lifter (tappet) on the 5.9L Cummins diesel engine, requiring removal of valve cover, rocker assembly, and pushrod to access the lifter.

Warnings

Tools required

Parts

• Valve lifter (tappet) × 1 — Use OEM specification - Cummins part
• Valve cover gasket × 1 — Use OEM specification
• Rocker lever assembly gasket/seal (if equipped) × 1 — Use OEM specification
• Valve cover bolt grommets × 1 — Use OEM specification
• Assembly lube (Cummins approved) × 1 — Use manufacturer-approved camshaft assembly lube

Fluids

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

Preparation

1. Verify engine is completely cold before beginning work
2. Disconnect both negative and positive battery cables to prevent accidental starter engagement
3. Remove engine cover/doghouse if equipped
4. Clean the entire valve cover area thoroughly with degreaser to prevent contamination
5. Position a large drain pan under the engine
6. Ensure adequate workspace lighting and ventilation
7. Have a clean workspace prepared for laying out rocker arms and pushrods in order
8. Take photographs or label all components during disassembly to ensure correct reassembly order
9. Verify replacement lifter is correct part number for this specific engine (early vs late 2007 may differ)

Procedure

1. 1

   Remove valve cover
   Disconnect any wiring harnesses, breather tubes, and fuel lines attached to or crossing the valve cover. Remove the valve cover bolts, then lift the cover away. Carefully lift the valve cover straight up to avoid damaging sealing surfaces. If stuck, gently tap with a rubber mallet - never pry between sealing surfaces.
2. 2

   Document valve positions and identify target cylinder
   The 2007 5.9L Cummins is a 24-valve engine (4 valves per cylinder - 2 intake, 2 exhaust, actuated via crossheads/bridges). Cylinders are numbered 1-6 from front to back. Verify which cylinder and which valve set corresponds to the failed lifter. Verify which cylinder and valve correspond to the failed lifter. Mark this clearly. Take detailed photos of rocker arm orientation and positions.
3. 3

   Rotate engine to release tension on target valve
   Using the Cummins barring tool inserted into the flywheel housing barring port (or a socket on the crankshaft damper bolt with caution), rotate the engine clockwise (viewed from front) until the target valve's rocker arm is on the base circle of the cam (pushrod and rocker will have slight play - not under spring pressure). This is critical to remove the rocker without fighting valve spring pressure. Mark the balancer position with paint marker for reference.
4. 4

   Remove rocker lever and bridge assembly
   The 5.9L uses a rocker lever/bridge assembly. Loosen the rocker lever adjusting screw lock nut, then back out the adjusting screw several turns to relieve all tension. Remove the rocker lever retaining bolts. Carefully lift the rocker bridge assembly straight up. Note the rocker shaft orientation and any shims present. Place components in order on your clean workspace.
5. 5

   Remove pushrod
   Lift the pushrod straight up and out of the engine. Inspect the pushrod ends for wear, scoring, or mushrooming. Check that the pushrod is straight by rolling on a flat surface - any wobble indicates replacement needed. If reusing, mark which end was up and store in a clean location. The pushrod must go back in the same orientation.
6. 6

   Extract the lifter
   Using a magnetic pickup tool, carefully extract the lifter from its bore. The lifter may be stuck due to varnish buildup. If stuck, use a specialized lifter removal tool - never pry or use excessive force which can damage the bore. Once removed, immediately inspect the lifter face and cam lobe for scoring, pitting, or spalling. Inspect the lifter bore for scoring or damage.
7. 7

   Inspect camshaft lobe
   Using a flashlight and inspection mirror, carefully examine the camshaft lobe that contacts the removed lifter. Look for pitting, scoring, flat spots, or irregular wear patterns. If the cam lobe shows damage, the camshaft must be replaced - installing a new lifter on a damaged lobe will cause immediate failure. Wipe the lobe clean with brake cleaner and lint-free cloth.
8. 8

   Prepare and install new lifter
   Thoroughly clean the lifter bore with brake cleaner and lint-free cloth. Coat the new lifter body with clean engine oil. Apply Cummins-approved assembly lube generously to the lifter face (cam contact surface). Carefully lower the new lifter into the bore, ensuring it slides smoothly. The lifter should drop into place with only minimal resistance. If excessive force is needed, stop and inspect for debris or damage.
9. 9

   Install pushrod and verify free rotation
   Coat both ends of the pushrod with assembly lube. Install the pushrod in the same orientation as removed, seating the lower end into the lifter cup. Rotate the pushrod with your fingers - it should spin freely in the lifter socket. Ensure the upper end is properly seated in the rocker arm socket pocket.
10. 10

    Reinstall rocker assembly
    Install any shims in their original positions. Place the rocker bridge assembly back onto the cylinder head, ensuring proper orientation and alignment with the pushrod ends. Install rocker lever retaining bolts and tighten gradually in a cross pattern. Tighten the rocker lever capscrews to the factory specification (approximately 27 ft-lb / 36 Nm for the 24-valve 5.9L Cummins), but confirm the exact value and any staged torque sequence in the factory service manual before final assembly.
11. 11

    Adjust valve lash (CRITICAL STEP)
    Rotate the engine to position the target cylinder at TDC compression stroke (both valves closed, rocker arms loose). For the 5.9L 24-valve Cummins, valve lash specification (cold) is typically 0.010 in (0.254 mm) intake and 0.020 in (0.508 mm) exhaust - verify with factory manual as specs may vary by build date. Using feeler gauge, loosen adjusting screw locknut, turn adjusting screw until specified clearance is achieved between rocker arm and crosshead. Hold the adjusting screw and torque the locknut to the factory specification (approximately 18 ft-lb / 24 Nm for the 24-valve Cummins - verify in the factory service manual). Recheck clearance after tightening.
12. 12

    Verify all valve clearances
    Since the valve cover is off, verify all valve lash clearances on all cylinders. This ensures no other issues are present and confirms proper reassembly. Use the firing order 1-5-3-6-2-4 and rotate engine to check each cylinder at TDC compression. Document all clearances for future reference.
13. 13

    Clean and prepare valve cover mating surfaces
    Remove all old gasket material from both the valve cover and cylinder head using a plastic scraper. Be extremely careful not to gouge aluminum surfaces. Clean thoroughly with brake cleaner and ensure surfaces are completely dry. Inspect for warpage or damage. Any imperfections will cause oil leaks.
14. 14

    Install valve cover with new gasket
    Install new valve cover gasket and grommets. Position valve cover carefully to avoid pinching gasket. Install bolts with new grommets and tighten in a crisscross pattern from center outward in 3 stages. Without specific torque values, the valve cover bolts on the 24-valve Cummins are low-torque fasteners (approximately 18 in-lb / ~2 Nm) - verify with the factory manual; overtightening will crush the gasket and cause leaks.
15. 15

    Reinstall accessories and perform oil change
    Reconnect all breather tubes, wiring harnesses, and fuel lines. Perform a complete engine oil and filter change using 15W-40 diesel oil or 5W-40 synthetic (approximately 12 quarts with filter - verify capacity in owner's manual). This removes any potential contaminants introduced during service. Reconnect battery cables.

Reassembly

1. Ensure all valve lash clearances are within specification before final assembly
2. Verify valve cover bolts are torqued in proper sequence to avoid gasket leaks
3. Double-check that no tools or rags remain in the engine
4. Confirm all electrical connections and fuel lines are properly secured
5. Replace engine oil and filter as contamination may have occurred during service

Verification

• Start engine and verify normal oil pressure immediately (should read 10+ psi at idle when warm, 30-60 psi at operating RPM)
• Listen for valve train noise - properly adjusted valves will have minimal ticking; excessive noise or knocking indicates misadjustment
• Inspect valve cover for oil leaks after 5 minutes of operation
• Allow engine to reach operating temperature and verify no abnormal noises
• Perform a test drive and monitor for normal power delivery and smooth operation
• Recheck valve cover for leaks after engine cools
• After 500 miles of operation, recheck valve lash on all cylinders as new lifters may seat slightly
• Monitor oil consumption and quality for the first 1000 miles to ensure proper lifter operation

More procedures for this vehicle