From the 5.9L 12V HX35W that started the Cummins performance scene to the 6.7L HE300VG VGT in today's Ram 2500 and 3500, Boost Lab rebuilds every generation of Cummins ISB turbocharger. We also cover ISX and X15 Class 8 applications. Ship your turbo nationwide.
The Cummins ISB went through five distinct turbocharger generations across its production run. Each has its own rebuild considerations, failure patterns, and performance upgrade options.
The HX35W on the 12V 6BT is the turbo that built the Cummins performance reputation. Straightforward journal bearing design, no electronic components, extremely rebuildable. The early version (1994-1996) uses an 8-blade compressor wheel; the later version uses 7 blades. Both are interchangeable for rebuild purposes. The most popular performance platform in the 5.9L community: upgraded compressor wheels and larger housings are widely available and significantly expand the power ceiling over stock.
The 24V ISB transitioned from the HX35W to the HY35W. The HY35W was fitted to automatic transmission applications in 2001-2002; manual trucks continued with the HX35W through this period. Both are journal bearing fixed-geometry units with no electronic components, which makes for clean, straightforward rebuilds. The same compressor wheel upgrade options available on the 12V HX35W apply here.
Two distinct turbos across this generation. The HE341CW (2003-2004.5) uses a 58mm compressor wheel matching the HY35W. The HE351CW (2004.5-2007) steps up to a 60mm compressor wheel and adds a built-in wastegate solenoid, the first Cummins ISB turbo with integrated electronic boost control. Confirm the specific model before ordering rebuild parts: the HE341CW and HE351CW share a similar appearance but are not interchangeable. The HE351CW is the most commonly rebuilt 5.9L turbo.
The 6.7L introduced variable geometry to the Ram pickup lineup. The HE351VE uses an electronic actuator to control VGT vane position, enabling the exhaust brake function and improving low-RPM response over the fixed-geometry 5.9L units. The actuator requires calibration after replacement; see the calibration note above. Stuck vanes from EGR soot accumulation are the primary failure mode on this generation. The actuator is a separate service item from the turbo rebuild itself.
The HE300VG replaced the HE351VE in 2013 with a more compact housing design and updated vane geometry. It is used on Ram 2500/3500/4500/5500 through the current production year. Like the HE351VE, VGT vane sticking from EGR soot is the primary failure mode. The HE300VG and HE351VE are not interchangeable: if your truck is 2013 or newer it takes the HE300VG; 2007.5-2012 takes the HE351VE. The actuator calibration requirement applies equally to both.
Search by year, model, turbo designation, or part number to confirm your application before submitting a rebuild request.
| Turbo | Application | Years | Type | Key Part Numbers | Notes |
|---|---|---|---|---|---|
| HX35W | Ram 2500 / 3500, 5.9L 12V 6BT | 1994-1998 | Fixed | 3539369 / 3802992 / 4864283 / 3590104 / 3590105 | 8-blade early / 7-blade late; strong performance platform |
| HX35W | Ram 2500 / 3500, 5.9L 24V ISB | 1998.5-2000 | Fixed | 4864283 / 4761339 / 3800799 | Same turbo as 12V; billet wheel upgrade available |
| HX35W | Ram 2500 / 3500, 5.9L 24V ISB Manual | 2001-2002 | Fixed | 3590104 / 3590105 / 48566400 | Manual transmission only; auto gets HY35W |
| HY35W | Ram 2500 / 3500, 5.9L 24V ISB Auto | 2001-2002 | Fixed | 3599811 / 3599810 / 4089392 / 4036329 | Automatic transmission only |
| HE341CW | Ram 2500 / 3500, 5.9L ISB | 2003-2004.5 | Fixed | 3591778 / 3592087 / 3800560 | 58mm compressor; NOT interchangeable with HE351CW |
| HE351CW | Ram 2500 / 3500, 5.9L ISB | 2004.5-2007 | Fixed | 4043600 / 4036835 / 4037001 / 4089797 / 4089673 | 60mm compressor; integral wastegate solenoid |
| HE351VE | Ram 2500 / 3500, 6.7L ISB | 2007.5-2012 | VGT | 3771639 / 3786226 / 3786775 / 3791741 / 3791778 | Electronic actuator; calibration required |
| HE300VG | Ram 2500 / 3500, 6.7L ISB | 2013-2018 | VGT | 3787604 / 3787605 / 3779989 / 3781754 / 3794757 / 5326057 | Updated vane geometry |
| HE300VG | Ram 2500 / 3500 / 4500 / 5500, 6.7L ISB | 2019-present | VGT | 5326047 / 5326054 / 5456364 / 5456365 / 68444771AA | Updated actuator; confirm year at teardown |
| HE400VG | Cummins ISX15 / X15, Class 8 | 2010-present | VGT | 2882112 / 3796351 / 3791991 (actuator) | 12V and 24V actuator variants; confirm voltage |
| HE451VE | Cummins ISX15, Class 8 | 2007-2012 | VGT | 4034289 / 4034290 / 3776172 / 4032760 | Calibration required; actuator repair available |
| HE300VG | Cummins ISL / ISC, Medium Duty | Various | VGT | Various, contact us | Vocational / medium duty; confirm application |
6.7L HE351VE • HE300VG
The single most common 6.7L Cummins turbo failure. The EGR system routes exhaust gas back through the intake, and soot from that exhaust accumulates on the VGT vane assembly over time. When the vanes stick, the turbo loses variable geometry function: boost comes on wrong, the exhaust brake stops working, and fault codes appear. Using the exhaust brake regularly is the most effective preventive measure, since it exercises the vanes and keeps them from cementing in place. At rebuild the vane assembly, unison ring, and nozzle ring are cleaned and inspected.
6.7L • ISX HE400VG
The electronic VGT actuator controls vane position and is a separate failure point from the turbo itself. A failed actuator presents as fault codes, boost irregularities, or engine derate. Calibration is required after any actuator replacement using Cummins INSITE, the Holset E-Tool, or compatible diagnostic equipment. The actuator on ISX applications comes in 12V and 24V variants: installing the wrong voltage actuator means an immediately dead unit. Confirm your system voltage before sourcing a replacement.
All Generations
The 6.7L Cummins EGR cooler is a known failure point. When an EGR cooler fails it can introduce coolant into the oil system, and that contaminated oil goes through the turbo bearings. Any 6.7L that has had an EGR cooler failure should have the turbo inspected before returning to service: coolant-contaminated oil destroys turbo bearings quickly and silently. On older 5.9L trucks, extended oil change intervals and sludge buildup in the oil passages are the equivalent concern.
All Generations • Tuned 5.9L
Intake-side foreign object damage contacts the compressor wheel at operating speed and causes immediate imbalance. On the 5.9L, heavily tuned trucks running the HX35W or HE351CW beyond their designed flow range experience compressor surge: a cyclical stall condition that hammers the thrust bearing and fatigues the compressor wheel. A surging turbo makes a distinctive fluttering sound under boost. The wheel is inspected at teardown and documented before any rebuild quote is issued.
All Generations
Shutting down a hot diesel without a cooldown period allows residual oil in the bearing housing to cook with no oil flow to carry the heat away. This is particularly relevant to work trucks and tow rigs that get pushed hard and then shut down immediately. A 2-3 minute idle after sustained high-load operation significantly extends bearing life. On turbocharged diesels used for towing, a turbo timer or manual cooldown discipline is one of the lowest-cost reliability habits available.
5.9L HE351CW 2004.5-2007
The HE351CW introduced an integral electronic wastegate solenoid, a first for the 5.9L ISB. The solenoid controls boost pressure and can fail electrically or mechanically. A failed solenoid presents as overboost or underboost depending on whether it sticks open or closed. It is distinct from the VGT actuator on the 6.7L but serves a similar boost control function. The solenoid is inspected at every HE351CW rebuild and replaced if out of spec.
Start a rebuild request online. Ship your turbo to Dade City, FL and we handle teardown, rebuild, and VSR balancing before it ships back.
Start Your Rebuild37833 Pineapple Ave Unit A • Dade City, FL 33523 • sales@theboostlab.com