A Look at the Holset Turbo
February 24, 2022

A Look at the Holset Turbo

Written By: ProSource Diesel

A Turbo Industry Leader

Holset turbochargers are an important part of Cummins engines, and Holset is a world leader when it comes to turbo technology. The Holset name has a long history, but now the company is known as Cummins Turbo Technologies.

Holset got started in 1952 when founders Paul Croset and Brian Holmes combined part of their last names to form the Holset company. Turbocharger technology was seeing a rapid rise in use in the 1950s for commercial engines, and Holset was poised to be on the cutting edge of this industry. By 1973, Holset had manufactured a total of one million turbochargers with many more on the way.

In the present day, the Holset name is closely linked with the Cummins brand of diesel engines. So closely linked in fact, that the company’s most well-known name now is Cummins Turbo Technologies. Holset turbos are the stock turbos in Cummins medium to heavy-duty engines.

Holset HE351VE Turbocharger


This is the stock turbo for the 6.7-liter Cummins engines made between 2007.5 and 2019. It is part of the HE300 turbocharger model series by Holset. Turbochargers in this model series are able to fit engine sizes up to 10 liters. The output range is between 90 and 240, and the airflow is 0.46. The length of this turbocharger is 250 mm with a width of 240 mm and a height of 220 mm.

Holset HE351CW Turbocharger


The HE351CW is the stock Holset turbo for the later versions of the 5.9-liter Cummins engines from 2004.5 to 2007. It’s also part of the HE300 Turbocharger model series and thus shares many of the same specs as the HE351VE turbo. You can get this turbo in an OEM replacement model or as a remanufactured model. This turbo is a fixed geometry design with an electronically controlled wastegate to more easily manage the boost to drive pressure ratio.

Holset HE341CW Turbocharger

This is the stock turbo for 2003 and 2004 Cummins engines. It replaced the Holset HX35W turbo. As a fixed geometry turbocharger, the HE341CW used journal bearings and a seven-blade compressor wheel. This turbo utilized a mechanical internal wastegate to avoid excessive drive pressure and overspeeding.

Holset HY35W Turbocharger

Holset HY35W Turbocharger

Holset HY35W Turbocharger


This is the stock turbo for earlier versions of the 5.9-liter Cummins. You can get both OEM versions of this turbo as well as remanufactured versions. Holset turbo rebuild kits are also available, and rebuilding this turbo is not particularly difficult.

The important thing is to have genuine Holset parts. You can easily see the difference between a genuine Holset journal bearing and a knockoff by the machined groove that spans the entire circumference of the bearing.

This groove is essential for proper lubrication in a genuine Holset bearing. This turbo is often misidentified as the HE341CW turbocharger due to how similar both turbos are.

Rebuilding the Holset HY35W Turbocharger

If you want to take on rebuilding a Holset HY35W Turbocharger, you’ll need an HY35W turbo rebuild kit. In general, this kit will include the following parts:

  1. Compressor wheel
  2. Turbine shaft and wheel assembly
  3. Marman clamp for turbine housing to bearing housing
  4. Oil supply tube fitting
  5. Oil supply tube
  6. Oil drain tube
  7. Up-pipe flange gasket
  8. Downpipe Marman clamp


Holset HY35W Turbo Rebuild Kit

Holset HY35W Turbo Rebuild Kit


The Holset turbo rebuild kit should include most of what you need, and the extra parts are generally parts that you don’t want to reuse when it comes to reinstalling the turbo. Not included but important to also have is some high-temp anti-seize lubricant for step #9 below.

Along with having all the right parts, it’s important to have a clean workspace and plenty of time and patience to rebuild your turbo.

The following are the basic steps for rebuilding:

  1. 1. Inspect the compressor wheels to see if they can be reused. The blades should not have any excessive wear.
  2. 2. The thrust bearing and small oil ring seal should be soaked in clean engine oil before being fitted together.
  3. 3. The large oil ring should also be soaked in this manner and then installed onto the turbine wheel shaft.
  4. 4. Soak the snap rings and journal bearings in the same manner, then fit the lower snap ring on the center section where the compressor is.
  5. 5. Install the journal bearing and then the upper snap ring.
  6. 6. The thrust collar, thrust washer, and thrust bearing all should be soaked in clean engine oil and then installed.
  7. 7. After installing the oil baffle and oil cap assembly, you can install the entire oil seal assembly into the center section.
  8. 8. Put the center cartridge and compressor wheel back together after soaking in clean engine oil. Torque the wheel to 133 inch-pounds of torque if the shaft has a six-point nut. If the shaft uses a 12-point nut, then torque to 124 inch-pounds.
  9. 9. Use the high-temp anti-seize lubricant to coat the entire sealing surface of the turbine housing.
  10. 10. Install the turbine housing to the center section and then add the Marman clamp. The clamp should be torqued to 75 inch-pounds.

The last steps are to reinstall the wastegate actuator and silencer ring. All bearings should be fully pre-lubed before operation.

Find the Holset turbo parts you need to replace or rebuild your Holset turbo by relying on ProSource Diesel. We carry the parts for the 5.9-liter and 6.7-liter Cummins engines using different versions of Holset turbochargers.

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