Turbocharger

This procedure covers removal and replacement of the Holset HE351CW turbocharger on the 5.9L Cummins diesel engine, including all intake and exhaust connections.

Warnings

Tools required

Parts

• Turbocharger assembly (Holset HE351CW or equivalent) × 1 — Use OEM specification
• Turbocharger oil feed line crush washers × 2 — Use OEM specification
• Turbocharger oil drain gasket × 1 — Use OEM specification
• Exhaust manifold to turbo gasket × 1 — Use OEM specification
• Turbo outlet to downpipe gasket × 1 — Use OEM specification
• Intake horn clamps × 2 — Use OEM specification
• V-band clamp (turbo to downpipe) × 1 — Use OEM specification
• Anti-seize compound × 1 — High temperature rated

Fluids

• 15W-40 diesel oil or 5W-40 synthetic — 1 qt

Preparation

1. Ensure engine is completely cold to the touch
2. Disconnect both negative and positive battery cables
3. Raise vehicle and support securely on jack stands
4. Remove the engine cover by pulling upward on the front edge
5. Apply penetrating oil to all exhaust fasteners and turbocharger mounting hardware, allow to soak for at least 30 minutes
6. Place drain pan under turbocharger oil drain area

Procedure

1. 1

   Remove air intake system
   Loosen the clamp at the air filter housing outlet and disconnect the intake tube. Remove the intake grid heater wiring connector. Loosen the clamp at the turbocharger compressor inlet and remove the entire intake horn assembly. Inspect the intake horn for oil residue which may indicate worn seals in the old turbocharger.
2. 2

   Disconnect intercooler system
   Loosen the clamp connecting the turbocharger compressor outlet to the intercooler tube. Carefully wiggle and remove the tube from the turbo outlet. Cap or plug the intercooler tube to prevent debris entry.
3. 3

   Disconnect turbo actuator and sensors
   Locate the wastegate actuator on the turbocharger. The HE351CW is a wastegated turbo with a mechanical (boost-pressure) actuator, so there is no electronic actuator connector to disconnect. Disconnect the wastegate actuator boost signal hose. If equipped, disconnect any exhaust back pressure or exhaust gas temperature sensors in the turbo/downpipe area. If equipped, disconnect the exhaust back pressure sensor and exhaust gas temperature sensor from the turbocharger and downpipe area.
4. 4

   Remove oil feed line
   Locate the oil feed line banjo bolt at the top of the turbocharger. Using a combination wrench, remove the banjo bolt and carefully pull the feed line away from the turbo. Discard the copper crush washers - these must be replaced. Plug the oil feed port on the turbocharger with a clean shop towel to prevent debris entry.
5. 5

   Remove oil drain tube
   From underneath the vehicle, locate the oil drain tube connecting the bottom of the turbocharger to the engine block. Remove the bolts securing the drain tube to both the turbocharger and the engine block. Pull the drain tube down and away, allowing any residual oil to drain into your pan. Remove and discard the gasket.
6. 6

   Disconnect exhaust downpipe
   Locate the turbine outlet flange connecting the turbocharger to the exhaust downpipe. The factory 5.9L HE351CW typically uses a bolted flange (verify whether your configuration uses a bolted flange or V-band clamp). Remove the flange bolts (or V-band clamp bolt), separate the connection, and carefully pull the downpipe away from the turbo outlet. Support the downpipe with wire or a stand to prevent stress on downstream exhaust components.
7. 7

   Remove turbocharger mounting nuts
   From the top and bottom of the engine bay, locate all turbocharger mounting nuts (the HE351CW typically uses 4 nuts) connecting the turbocharger to the exhaust manifold. Work slowly and carefully, as these studs are prone to breaking. Remove all mounting nuts and set aside. If a stud breaks, it must be extracted before installing the new turbocharger.
8. 8

   Remove turbocharger assembly
   With all connections and mounting hardware removed, carefully work the turbocharger away from the exhaust manifold studs. The turbo is heavy and awkward - use both hands and proper lifting technique. Once free, lower the turbocharger down and remove from the engine bay. Remove and discard the exhaust manifold gasket.
9. 9

   Clean mounting surfaces
   Thoroughly clean the exhaust manifold mounting face using a gasket scraper and wire brush. Remove all carbon deposits and old gasket material. Inspect the manifold studs - if any are damaged or broken, they must be replaced before proceeding. Clean the oil drain mounting surface on the engine block. Verify all passages are clear of debris.
10. 10

    Prepare new turbocharger
    Remove the new turbocharger from packaging. Remove all shipping plugs from the oil feed, oil drain, compressor inlet, and compressor outlet ports. Pour approximately 1/2 quart of clean engine oil into the turbo oil inlet while slowly rotating the compressor wheel by hand to pre-lubricate the bearings. This critical step prevents bearing damage during initial startup.
11. 11

    Install new turbocharger
    Position the new exhaust manifold gasket onto the manifold studs. Apply a thin coat of anti-seize to the exposed threads of the exhaust manifold studs. Carefully lift the new turbocharger into position, aligning the mounting holes with the exhaust manifold studs. Thread all mounting nuts on by hand to ensure proper alignment before tightening.
12. 12

    Torque turbocharger mounting nuts
    Working in a cross-pattern, gradually tighten all turbocharger mounting nuts. The factory specification for the turbo-to-manifold nuts on the 5.9L Cummins is approximately 32 ft-lbs (43 Nm); verify against the service manual before proceeding.
13. 13

    Reinstall oil drain tube
    Install the new oil drain gasket onto the turbocharger drain port. Position the oil drain tube and install mounting bolts at both the turbocharger and engine block. Tighten securely but do not overtighten - these typically require 18-22 ft-lbs of torque.
14. 14

    Reinstall oil feed line
    Install new copper crush washers on both sides of the oil feed line banjo fitting. Position the oil feed line to the turbo inlet and install the banjo bolt. Tighten the banjo bolt to the factory specification (approximately 15-18 ft-lbs / 24 Nm); verify before proceeding. Ensure the feed line is routed properly without kinks or contact with hot exhaust components.
15. 15

    Reconnect exhaust and intake systems
    Reconnect the exhaust downpipe to the turbocharger outlet using the factory connection method (bolted flange with new gasket, or V-band clamp if so equipped). Tighten securely. Install the intercooler tube to the compressor outlet with a new clamp. Install the intake horn to the compressor inlet with new clamps. Reconnect the wastegate actuator boost hose and any exhaust sensors. Verify all connections are secure and properly routed.

Reassembly

1. Double-check that all electrical connectors, vacuum lines, and clamps are properly secured
2. Verify the V-band clamp at the downpipe is properly seated and tightened
3. Ensure no tools or shop towels remain in the engine bay
4. Reinstall the engine cover
5. Reconnect the battery cables (positive first, then negative)
6. Lower the vehicle from jack stands

Verification

• With the vehicle in park and parking brake set, start the engine and allow it to idle
• Monitor for any oil leaks at the feed line, drain tube, and turbocharger seals during the first few minutes of operation
• Listen for any unusual noises from the turbocharger - there should be no grinding, squealing, or rattling sounds
• Check that boost pressure builds normally when accelerating - the turbo should spool smoothly without hesitation
• Verify no exhaust leaks are present at the manifold connection or downpipe V-band clamp
• After initial test drive, re-inspect all connections and verify no leaks have developed
• Check engine oil level and top off if necessary after turbocharger has been pre-lubricated

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