Rebuilt or Remanufactured Cummins Water Pumps – Pros and Cons

Keeping an eye out for the symptoms of a failing water pump is an important part of diesel engine maintenance, as total water pump failure can lead to catastrophic engine problems.

If your Cummins water pump does fail, you have two options for replacement: a rebuilt/remanufactured water pump or a brand new one. There’s a lot of debate over which choice is better, so it’s important to weigh the pros and cons.

Kenworth truck

The Cummins ISX12 and ISX15 – available on the T680 – are the newest engines in a long line of popular and successful Cummins HD truck engines. Image copyright SASgrafix.

Rebuilt/Remanufactured Water Pumps


The two big upsides to rebuilt water pumps for a Cummins engine are:

  • They are often (but not always) cheaper in terms of up-front cost
  • Some shops are equipped to do most of the rebuild themselves rather than paying for a rebuilt unit off the shelf

This means significant parts savings for the engine’s repair.


While parts savings are significant and worth keeping in mind, there are also downsides to rebuilt units:

  • A nominal warranty, if any at all
  • A lack of standards in terms of deciding which parts are replaced, what tolerances are acceptable, and if exact fit replacement components are used or not
  • Chances of failure are much higher than with a new unit

Depending on the quality of the rebuild, the water pump may have unexpected problems not noticed during the rebuild process. A bad impeller is not always noted on visual inspection, for example, and can lead to a less efficient unit that fails sooner than expected.

Another thing to note is that rebuild kits have oversized bearings meant to compensate for wear that’s been had on the shaft and housing. This can cause failure down the line as these bearings are often not a perfect fit.


Calling the wrecker is never good times. Rebuilt and remanufactured water pumps have a statistically higher chance of failing than brand new water pumps, all things being equal. Image copyright Alf van Beem.

Additionally, the blasting process that’s used to clean pump housings can lead to pitting and early corrosion issues.

New Water Pumps

GMB hd pump

GMB currently offers brand new water pumps for Cummins applications that are cost competitive with rebuilt and remanufactured OEM water pumps.

Despite a remanufactured unit’s new components, it’s still nowhere close in quality to a new water pump as the quality of remanufactured materials isn’t always OEM-spec. Remanufacturing a water pump with some new materials simply doesn’t compare to a new pump made entirely from new materials.

While it’s commonly believed that rebuilt or remanufactured Cummins water pumps are less expensive than brand new water pumps, companies like GMB are challenging that belief. New HD Water Pumps from GMB are often cost comparable to rebuilt and remanufactured water pumps, making them a superior alternative to buying a rebuilt or remanufactured unit.

What’s more, even if a new water pump has a higher initial cost, new units can offer cost savings down the road. The statistical likelihood of a brand new water pump failing are quite low compared to a remanufactured or rebuilt water pump. The costs of failure can be massive, as water pump failure can lead to extensive engine damage in a worst-case scenario. At the very least, water pump failure will lead to downtime that can be costly.

Many OEM-quality water pump manufacturers, such as GMB, are offering brand new HD Water Pumps at a price that’s less than (or close to) the price of a rebuilt or remanufactured Cummins water pump. Considering the costs are so close, the benefits of going with a new unit almost certainly outweigh any reason to go with a remanufactured or rebuilt water pump.


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