Introduction: Holset — The Original Cummins Turbocharger
If your engine carries a Cummins badge, the chances are overwhelming that its turbocharger is a Holset. Acquired by Cummins in 1973 and now operating as Cummins Turbo Technologies (CTT), Holset is the exclusive OEM turbocharger supplier for all Cummins diesel engines worldwide. From the compact HE200WG on a QSB4.5 excavator engine to the massive HE800VGT on a Cummins QSK50 mining power plant, Holset covers the widest power range of any single turbocharger brand in the heavy-duty market.
For fleet operators, parts distributors, and diesel workshops supplying Cummins-powered heavy trucks, construction equipment, generator sets, and marine engines across Africa, the Middle East, South America, Southeast Asia, and South Asia — maintaining availability of Holset HX and HE series turbochargers is essential to minimizing equipment downtime. This guide covers Holset’s model naming system, the most commercially important Holset series for global aftermarkets, failure diagnosis, and how HHX Parts supplies Holset-compatible turbochargers factory-direct.
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Holset Turbocharger Model Naming System
Understanding Holset’s naming convention is the first step to correct part identification.
HX Series (Fixed-Geometry, Wastegate)
HX 35 W
│ │ └── W = Wastegate (boost pressure controlled by wastegate actuator)
│ └── 35 = approximate compressor wheel inducer diameter in mm (35mm ≈ frame size)
└── HX = Holset eXchange / standard series (fixed-geometry wastegate turbo)
The HX series covers the majority of Holset’s volume production for commercial diesel engines. Frame sizes range from HX25 (small to medium bore 4–6 cylinder) to HX80 (large bore multi-cylinder).
HE Series (Electronic/Variable-Geometry)
HE 400 VG
│ │ └── VG = Variable Geometry (variable nozzle turbine)
│ └── 400 = approximate turbine/frame size code
└── HE = Holset Electronic (electronically controlled or VGT variant)
The HE series represents Holset’s modern electronically-controlled and variable-geometry designs for Euro 3+ emissions-compliant engines. The HE200 through HE800 cover small commercial to ultra-large mining/power generation engines.
Common Suffix Codes
| Suffix | Meaning |
|---|---|
| W | Wastegate actuator (internal or external) |
| VG / VGT | Variable Geometry Turbine |
| G | Generator / industrial application variant |
| M | Marine application variant |
| S | Stage 1 (calibration variant) |
Holset HX Series: Most Important Models for Global Aftermarket
HX25 / HX27 — Light to Medium Commercial
Frame size: Approximately 25–27mm compressor inducer
Power range: 75–175 hp
Typical applications:
- Cummins 4BT 3.9L (light trucks, agricultural, marine under 150 hp)
- Cummins B3.9 / QSB3.9 (compact equipment)
- Iveco NEF 4-cylinder (some specifications)
Market relevance: HX25/27 units serve the light-medium commercial segment and are common in South Asia (India’s light trucks using Cummins B-series) and early-generation construction equipment.
HX35 — The Most Widely Distributed Holset
Frame size: Approximately 35mm compressor inducer
Power range: 185–350 hp
Typical applications:
- Cummins 6BT 5.9L (12V) — medium trucks, Dodge Ram, agricultural equipment (NH/NTA855 early transition)
- Cummins 6BTAA 5.9L — marine and generator applications
- Cummins ISB 5.9L — medium-duty truck and bus
- Cummins B5.9 / C8.3 — construction equipment
- Iveco Cursor 9 (some specifications)
- JCB 750 series agriculture (Cummins-powered)
Market relevance: The HX35 is the single highest-volume Holset aftermarket unit globally. Cummins 6BT-powered equipment spans every continent — the HX35 is a core stocking item for any Cummins parts distributor. Particularly high demand in the Middle East (Dodge Ram fleets, construction equipment), South America (medium trucks, agriculture), and Africa (construction machinery).
HX40 — Medium-Heavy Truck Workhorse
Frame size: Approximately 40mm compressor inducer
Power range: 250–425 hp
Typical applications:
- Cummins N14 / NTC855 (turbocharged variants) — heavy-duty long-haul trucks, bus chassis
- Cummins ISC 8.3L — medium-heavy trucks, coaches
- Cummins M11 (early, pre-CELECT) — North American heavy truck
- Komatsu S6D102 / S6D107 (some specifications) — construction equipment
- Iveco Cursor 10 (some export specifications)
Market relevance: HX40 covers the critical 250–425 hp heavy truck and medium construction equipment range — a primary demand segment in Africa (heavy trucking), South America (freight), and the Middle East (construction logistics).
HX50 / HX52 — Heavy Truck and Large Industrial
Frame size: Approximately 50–52mm compressor inducer
Power range: 350–600 hp
Typical applications:
- Cummins NT855 / NTA855-G — stationary generator sets, industrial pumps
- Cummins KT1150 / KTA1150 — early K-series large equipment
- Cummins ISM 11L / ISMe — heavy-duty trucks (some specifications)
- FAW CA6DL2 and CA6SM2 (Cummins license) — Chinese heavy trucks
- Sinotruk WD615/WD618 with Cummins specifications
Market relevance: HX50/52 units power the large generator sets and heavy construction equipment that are the backbone of infrastructure projects across Africa, the Middle East, and South Asia. Chinese heavy truck (FAW, Sinotruk with Cummins engines) export markets drive additional demand.
HX55 / HX60 — Large Displacement, High Power
Frame size: Approximately 55–60mm compressor inducer
Power range: 450–750 hp
Typical applications:
- Cummins KT19 / KTA19 — large construction equipment, power generation, marine
- Cummins QST30 — large generator sets
- Cummins M11 (high-power variants)
- Large marine propulsion (ferries, offshore supply vessels)
Market relevance: HX55/60 units are critical components for the mining and oilfield sector — KTA19-powered equipment is found in quarrying, underground mining, and large construction sites across Africa, the Middle East, and Southeast Asia.
HX80 — Extreme Duty Mining and Marine
Frame size: Approximately 80mm compressor inducer
Power range: 700–1,200 hp (per turbocharger; K38 uses two)
Typical applications:
- Cummins K38 / KTA38 — mining haul trucks (Komatsu 730E, CAT 785), large generator sets
- Cummins K50 / KTA50 — ultra-large mining equipment and power generation
- Large marine propulsion (escort tugs, AHTS vessels)
Market relevance: HX80 units are specialty high-value items serving the mining sector in Chile, Peru, South Africa, DRC, and Kazakhstan. Each KTA38 engine uses two HX80 turbochargers — failure of one unit immediately halves engine power on a production-critical machine.
Holset HE Series: Modern Electronic and VGT Variants
HE200WG — Compact Electronic Wastegate
Aplicações: Cummins QSB4.5 and QSB6.7 (ISB) — excavators, wheel loaders, agricultural equipment (Cat 320, Volvo EC220, JD 210G power units)
The HE200WG uses an electronically-controlled wastegate for tighter boost management. It is one of the most frequently replaced turbochargers in the 20–30 ton excavator segment globally.
HE300VG / HE341VE — VGT for Euro 3–4 Trucks
Aplicações: Cummins ISB6.7, ISC, and ISL on Euro 3/4 trucks and buses; some Cummins-powered coaches
VGT units in this series use an electronically-controlled variable nozzle assembly. The actuator is the most common failure point — either the position sensor or the actuator motor. Diagnostic code P0046 (VGT actuator fault) is a primary trigger for replacement.
HE400VG — Heavy Truck VGT
Aplicações: Cummins ISM, ISX, X12, X15 on heavy-duty long-haul trucks (Peterbilt, Kenworth, Freightliner, International)
North American heavy truck market dominant. Also used on some export specifications for Middle East and Australian long-haul trucks.
HE500FG / HE551V — Large Industrial VGT
Aplicações: Cummins QSX15, ISX15, QST30 on large power generation and industrial applications; also Iveco Cursor 13 (FPT) on some specifications
Holset Turbocharger Failure Modes
Failure Mode 1: Oil Seal Leakage (Compressor Side)
Symptoms: Blue or white smoke on acceleration after idle; oil consumption without external leaks; oil-fouled compressor wheel and inlet
Cause: The compressor-end oil seal (piston ring or labyrinth seal) fails, allowing oil from the bearing housing to enter the compressor inlet. Primary causes: clogged crankcase ventilation (PCV) causing elevated crankcase pressure, contaminated oil, or end-of-life bearing wear.
Diagnosis: Inspect compressor inlet for oil residue. Check PCV system pressure — excess crankcase pressure pushes oil past the compressor seal even with a serviceable turbo. Confirm by measuring crankcase pressure (should be near-atmospheric or slightly negative).
Solution: Resolve PCV issue first, then replace turbocharger. Installing a new turbo without fixing the PCV system will fail the replacement within 10,000 km.
Failure Mode 2: Oil Seal Leakage (Turbine Side)
Symptoms: Heavy blue/black smoke from exhaust at all speeds; oil burned smell from exhaust; turbocharger oil consumption
Cause: Turbine-end seal failure allows oil to enter the exhaust stream where it burns. Causes include bearing wear, oil coking from inadequate cool-down time after high-load operation, or oil contamination.
Diagnosis: Inspect turbine outlet and exhaust manifold for oil residue — turbine-side leakage produces heavier oil deposits in the exhaust than compressor-side leakage.
Solution: Turbocharger replacement. Implement cool-down idle protocol (3–5 minutes at idle before shutdown) to prevent oil coking in the bearing housing.
Failure Mode 3: Bearing Failure (Foreign Object / Oil Starvation)
Symptoms: Loud whining or grinding noise from turbocharger; shaft play visible (axial or radial exceeding specification); compressor or turbine wheel contact marks on housing
Cause: Foreign object ingestion through air intake (most common cause of acute failure) or prolonged operation with degraded oil (soot-laden oil, incorrect viscosity, extended oil change intervals) causing bearing journal wear.
Diagnosis: Spin the turbo shaft by hand — rough or restricted rotation indicates bearing failure. Measure shaft axial play (specification typically under 0.09mm for HX35) and radial play (under 0.15mm).
Solution: Turbocharger replacement. Inspect and clean the entire air intake system to find and remove the foreign object source. Change engine oil and filter simultaneously with turbocharger replacement.
Failure Mode 4: VGT Actuator Failure (HE Series)
Symptoms: Check engine light with P0046 (VGT actuator position malfunction); loss of power; turbo boost limited to fixed minimum position; boost pressure erratic
Cause: The electronic actuator motor or position sensor fails from heat cycles, vibration fatigue, or water/contamination ingress through the actuator connector.
Diagnosis: Command the VGT actuator through its full range using a diagnostic scan tool — observe if the vane position feedback tracks the commanded position. Actuator not responding = motor failure. Position signal erratic = position sensor failure.
Solution: Actuator replacement first (less expensive than full turbocharger). If vanes are mechanically seized from carbon build-up, full turbocharger replacement or specialist VGT cleaning service required.
Failure Mode 5: Wastegate Failure (HX Series)
Symptoms: Overboost (P0234) if wastegate stuck closed; underboost (P0299) if wastegate stuck open; boost pressure does not respond to load changes as expected
Cause: Wastegate actuator rod seizes, actuator diaphragm ruptures, or wastegate flap sticks from carbon deposits (common on high-EGR engines).
Diagnosis: Apply regulated compressed air to the wastegate actuator port — the flap should move smoothly through its full range. Confirm return spring tension is adequate.
Solution: Actuator replacement or full turbocharger replacement depending on severity and component availability.
Holset Turbocharger Replacement: Key Installation Rules
- Pre-lube before starting — Fill the oil inlet port with clean engine oil and rotate the shaft by hand before connecting the oil supply line. This prevents dry-start bearing damage on initial startup.
- Change engine oil and filter simultaneously — Old oil contains metallic particles from the failed bearing; these will damage the new turbocharger’s bearings within hours if not removed.
- Inspect the oil supply line — A partially blocked oil feed line is a common cause of repeated turbocharger failure. Clean or replace the oil feed line and check the inline filter screen.
- Idle for 3 minutes after installation before loading — Allow oil pressure to fully prime the bearing housing before applying boost load.
- Implement cool-down idling — 3–5 minutes of idle after heavy-load operation prevents oil coking in the bearing housing.
- Check air intake system for leaks — Any post-filter air leak causes unfiltered air ingestion and rapid compressor wheel erosion. Inspect all hose clamps and boot conditions.
Markets Where Holset Turbochargers See Highest Demand
China — NTA855 and Cummins ISB/ISC Domestic Trucks
China’s domestic heavy truck market generated Holset’s largest single-country volume historically. Sinotruk HOWO, FAW Jiefang, and Shacman trucks powered by Cummins NTA855 and ISM/ISZ engines use HX50/52 and HE400VG turbochargers. The aftermarket for these units remains significant as pre-National IV fleets continue operating in regional markets.
Africa — Construction Equipment and Heavy Freight
Sub-Saharan Africa’s construction boom drives strong demand for:
- HE200WG (QSB4.5/QSB6.7) — dominant in Komatsu PC200-8/PC210-8 excavators used on road and building projects across East and West Africa
- HX35/HX40 — Cummins 6BT and ISC-powered medium trucks and construction equipment
- HX50/HX55 — Cummins KT19-powered generator sets and large equipment on mining and infrastructure projects
Middle East — Oilfield and Construction
The Arabian Peninsula and Iraq operate large fleets of Cummins-powered equipment:
- HE200WG/HE300VG — excavators and wheeled equipment on construction projects
- HX52/HX55 — KT19-powered generator sets for oilfield camps and remote facilities
- HX80 — K38-powered prime movers and drilling rig power trains
South America — Mining and Agriculture
Chile, Peru, and Brazil’s mining sectors drive demand for HX80 (K38/K50 haul trucks) and HX55 (KT19 medium mining equipment). Brazil’s agricultural equipment market uses Cummins-powered tractors and combines requiring HX35/HX40 replacement units.
South and Southeast Asia — Commercial Vehicle and Power Generation
India’s construction sector uses significant Komatsu and Hitachi excavator fleets (Cummins QSB-powered), driving HE200WG demand. Bus and coach applications across India (Cummins ISC-powered) require HX40/HE300VG units. Indonesia’s palm oil and coal mining sectors operate large Cummins generator sets requiring HX50/52 and HX55 units.
HHX Parts: Holset-Compatible Turbocharger Supply
HHX Parts supplies Holset-compatible turbochargers as the core of our product range. Holset covers the majority of our Cummins turbocharger inventory, and we stock units for the following key applications:
✅ In-Stock Cummins / Holset Turbocharger Range
Browse our existing Cummins turbocharger guides for specific models and OEM part numbers:
- Cummins Full Turbocharger Product Guide →
- South America Cummins Turbocharger Sourcing Guide →
- Turbocharger Fault Code Guide (P0299 / P0046 / P0234) →
✅ Related Cummins Engine Parts
- Cummins PT Fuel Pump Guide — injection system for NTA855, KT19, K38, K50
- Bosch CP3 Pump for Cummins QSB6.7 — common rail fuel pump for ISB/QSB engines
- All Injection Pumps →
- All Injectors & Nozzles →
Request a Quote for Holset Turbochargers
To receive pricing and availability for your specific Holset model, contact HHX Parts with:
- Cummins engine model (e.g., QSB6.7, ISB, NTA855-C360, KTA19-G3)
- Holset turbocharger number if visible on the nameplate
- Cummins OEM part number if available
- Equipment make and model (e.g., Komatsu PC210-8, CAT 320D)
- Required quantity and destination country
📧 Email: gzlh2022@gmail.com
📱 WhatsApp: +86 18170714612
HHX Parts — Factory-Direct Diesel Engine Parts
Guangzhou, China | Est. 2020
Holset / Cummins turbochargers • Fuel injectors • Injection pumps • Alternators • Starters
12-month warranty | OEM-grade quality | Worldwide shipping
