Cummins/Holset HY35 Turbocharger Rebuild Guide

2003-2004 5.9L Cummins ISB HY35W Turbocharger Rebuild Procedures

The Holset HY35W type D turbocharger is found in 2003 to 2004.5 model year Dodge Ram pickups powered by the 5.9L Cummins turbodiesel. It is often misidentified as a HE341 due to similarities between the two models. Rebuilding the turbocharger is not particularly difficult, although it does require a bit of patience and a clean work station. For disassembly information, see: Holset HY35W turbo disassembly procedures. The following procedures assume that the turbocharger has already been completely disassembled and thoroughly cleaned.

Holset HY35W Turbocharger Parts

Genuine Holset/Cummins Parts vs Cheap Aftermarket

The market is flooded with cheap, low quality turbocharger rebuild kits. While they are significantly less expensive than the genuine Holset products available through your local Cummins parts dealer, their quality is extremely questionable. These cheap imitation are being marketed as "Genuine" Cummins/Holset products at various online marketplaces. The simplest way to spot an imitation is to look at the journal bearings.

Holset journal bearing vs cheap aftermarket bearing

Genuine Holset bearing at left, cheap bearing at right.
Note the lubrication ring machined into the Holset bearing.

The OEM replacement bearings manufactured by Holset and sold through Cummins dealers feature a machined groove traveling the entire circumference of the bearing at its center. Note that this groove, which is important for proper lubrication, is absent from the imitation being sold as a genuine Holset product.

Holset thrust washer vs cheap aftermarket thrust washer

Genuine Holset thrust washer at left, cheap thrust washer at right.
The Holset washer is machined to a higher degree of precision than its cheap counterpart.

As with the Holset journal bearings, the OEM thrust washer is machined to a greater precision and has minute features that are absent from the imitation. We highly recommend rebuilding your turbocharger with genuine replacement parts and avoiding the cheap, foreign made alternatives on the market.

HY35W Turbocharger Rebuild Parts List

Part Description

Part Number

Notes

HY35W service kit

Holset 4031484

Includes journal bearings, oil seals, etc

Compressor wheel

N/A

Many aftermarket options available, i.e. billet compressor wheels

Turbine wheel/shaft assy

Holset 3519336

Replace as necessary; verify oil seal lands are not scarred

Turbine to bearing housing Marman clamp

Holset 4036551

Replace as necessary

Oil feed tube fitting

Cummins 4940183

Includes seals; recommend replacing during turbo service

Oil feed tube

MOPAR 68002982AA
Cummins 4935577

Replace as necessary; does not include fittings/seals

Oil drain tube gasket

Cummins 5264568

Required for reinstallation of turbocharger - do not reuse

Oil drain tube/hose

MOPAR 5086950AA

Replace as necessary; includes drain tube, hose, gasket, & seal

Up-pipe flange gasket

Cummins 3755843

Required for reinstallation of turbocharger - do not reuse

Downpipe Marman clamp

MOPAR 52103596AC

Replace as necessary

High temp anti-seize compound

Loctite LB 8009
Permatex 77124
Motorcraft XL-2

All products listed are rated up to 2,400 ° F

How to Rebuild a Holset HY35W Turbocharger

The turbocharger should be assembled on a clean workbench free of dust, debris, and contaminants. Turbos operate at incredibly high speeds, thus they should repaired with care. All o-rings, bearings, and related components should be coated (or soaked) in clean engine oil prior to installation to ensure proper sealing, fitment, and operation.

Click any thumbnail to view fullsize, detailed image

HY35 compressor wheel with worn blades/fins

• Compressor wheels are entirely reusable so long as they are not damaged and/or excessively worn. Thoroughly inspect the compressor for shape and form before making the decision to reuse.

• The edge of the blades on the compressor wheel inducer pictured at left have small wear marks indicating poor filtration; it will not be reused.

Thrust bearing

• Soak the thrust bearing and small oil ring seal in clean engine oil, then install the oil ring onto the appropriate land on the thrust bearing. Be cautious not to mar the sealing surfaces of the thrust bearing.

Turbine shaft oil ring seal

• Soak the large oil ring in clean engine oil, then install onto the appropriate land on the turbine wheel shaft. Be cautious not to mar the sealing surfaces of the turbine shaft assembly.

Bearing cartridge

• Soak the journal bearings and snap rings in clean engine oil. Install the lower snap ring on the compressor side of the center section.

Installing journal bearings on compressor side

• Install the journal bearing, followed by the upper snap ring that secures the bearing in place.

Installing thrust collar

• Coat the thrust collar in clean engine oil, then install atop the journal bearing with the wider portion sitting above the bearing.

Installing thrust washer

• Coat the thrust washer in clean engine oil, then install atop the thrust collar. Ensure the alignment pins engage the appropriate holes in the washer; orientation should match that pictured, i.e. do not install upside down, the position is vital to proper lubrication.

Installing thrust bearing in oil cap

• Install the thrust bearing into the oil cap. The oil ring should snap into place securely if installed correctly.

• Coat the oil cap o-ring in clean engine oil, then install on the oil cap.

• Install the oil baffle inside the oil cap.

• Thoroughly coat the entire assembly with clean engine oil.

Installing oil cap

• Install the oil seal assembly (with baffle, o-ring, and thrust bearing) into the center section. Secure with the appropriate snap ring, ensuring that the snap ring seats properly.

Installing journal bearing on turbine side

• From the turbine side, install the lower journal bearing snap ring, followed by the journal bearing, and finally the upper journal bearing snap ring (all components should have been soaked in clean engine oil).

Turbine wheel installed in center section

• Set the center cartridge on the workbench with the oil inlet facing upwards (small threaded hole, not the two bolt flange). Coat the entire turbine shaft, particularly around the oil seal, with clean engine oil and install the turbine wheel heat shield over the shaft.

• Insert the shaft into the center section with the oil ring gap facing upwards. The oil ring gap must align with the oil inlet location or a leak may develop. The oil ring will snap into place once properly seated; excessive force should not be required.

Compressor wheel installed

• Install the compressor wheel and torque to 133 in-lbs if shaft uses 6 point nut, 124 in-lbs if shaft uses a 12 point nut. Note - inch pounds, NOT foot pounds. If reusing a compressor wheel, ensure to line up index marks on tip of compressor wheel and shaft made during disassembly.

Prepping turbine housing for installation

• Coat the sealing surface of the turbine housing with a high temperature anti-seize lubricant.

Turbine housing installed to bearing housing

• Line up and install the turbine housing to the center section. Install the Marman clamp and torque to 75 in-lbs. Tap turbine housing with a dead blow hammer several times and re-torque.

Compressor housing installed

• Coat the compressor housing o-ring with clean engine oil (if applicable), then install on the appropriate flange of the center section.

• Line up and install the compressor housing; secure in place with large snap ring. Ensure that the snap ring is fully seated.

Wastegate actuator installed

• Reinstall wastegate actuator and wastegate actuator linkage.

• Reinstall silencer ring at compressor housing inlet.

• IMPORTANT - Turbocharger bearings must be pre-lubed before operating; after installing turbocharger onto exhaust manifold, install turbo oil drain tube. Pre-lube the turbocharger bearings by pouring a small quantity of clean engine oil through the turbo oil inlet while rotating the shaft via the compressor wheel. Finally, install the oil feed line.