What causes a diesel water pump to make unusual noises?

What causes a diesel water pump to make unusual noises?

Sponsored by GMB North America, Inc.

If a customer brings in a diesel vehicle with a water pump that is making unusual sounds, there’s likely an underlying problem. To help you pinpoint the causes(s) of the noise, we put together a list of the most common unusual noises diesel engine water pumps make.

1. Squeaking or clicking
If you hear a squeaking or clicking noise coming from the water pump, then it’s likely that the bearings are bad. The bearings support the shaft that connects the pulley and impeller. When they’re worn, they’ll make a squeaking or clicking sound because the shaft no longer rotates smoothly.

The bearings can be replaced in some water pumps, but usually it is more cost effective to replace the whole pump. If the bearings or pump aren’t replaced soon after the noise starts, then they’ll eventually break and other components may get damaged. The pump will have to be removed to replace the bearings, or course, to replace the pump. Don’t forget to check related components for damage, too.

2. Grinding or groaning
Sometimes a worn bearing will cause a grinding or groaning sound, but the cause is usually a bad water pump pulley. Driven by the serpentine or V belt, the pulley is responsible for rotating the water pump. When it’s cracked or warped, the pulley will wobble as it turns, resulting in a grinding or groaning noise.

Other signs of a bad pulley include:

  • Physical damage on the pulley;
  • Overheated engine; and/or
  • Worn or frayed belt edges.

If the pulley seems fine upon inspection, then check the serpentine or V belt, as a loose belt may make the same noise.

3. Rattling
A rattling noise coming from the water pump means that the bearings are in the early stages of going bad. Sometimes the rattling noise only occurs when the engine is still cold and then stops once it warms up. That doesn’t mean the water pump is okay. It will fail shortly.

Not sure what the noise is?
If you’re unsure what the noise is, here are a few things to check:

  • Serpentine (or V) belt – Inspect the belt for unusual wear, and check for proper tension.
  • Water pump pulley – With the engine running, look for side to side wobble.
  • Water pump – With the engine running, use a mechanic’s stethoscope to listen the water pump bearing. If it is bad, a grinding noise will be audible.
  • Water pump impeller shaft – With the engine off, loosen the belt tension. Check the side-to-side and forward and backward play in the shaft. There should be none that you can feel by hand.
  • Belt tensioner bearings – Many vehicles have one or more belt tensioners. When they fail, they can make a noise similar to a failing water pump. Loosen the belt tension, and check for play in the tensioner.

This article was sponsored by GMB North America, Inc. For more information, please visit our website at www.gmb.net

You May Also Like

How air quality impacts diesel engine air filtration

Just as you feel it when you breathe in air with a poor air quality index, your engine also feels it. 


As diesel engine aftertreatment systems became more and more efficient the adage in the trucking industry was that the air coming out of the tailpipe was cleaner than the air going into the engine. As air quality worsens across the globe that adage is quickly becoming a stark truism. Just as you feel it when you breathe in air with a poor air quality index, your engine also feels it. 

Don’t slack when it comes to heavy-duty truck slack adjuster inspection

The crucial role of slack adjusters in truck safety, understanding legal limits, and the innovative features offered by Motor Wheel

FUCHS Launches RENOLIT CSX AWE 0, a Sustainable Grease for Heavy Duty Truck Trailer Axles

FUCHS Lubricants Co. recently released RENOLIT CSX AWE 0, a calcium sulfonate complex grease for truck trailer axle hubs. When compared to the industry-standard legacy grease in a third-party side-by-side study, RENOLIT CSX AWE 0 exhibits improved low friction performance, lower running temperature, and improved extreme-pressure performance. Using this product, OEMs can expect better protection

The ABC’s of tire load capacity

By the time you finish reading this article, you’ll realize that ensuring optimal tire performance can be as easy as ABC.

Keep an eye on coolants in today’s advanced diesel engines

What to focus on when it comes to heavy-duty truck diesel engine coolant maintenance.


Other Posts

The true cost of bargain air spring spec’ing

Reproductions made of cheaper, less stable materials are on the rise in the global market.

Tire maintenance tips to avoid heavy-duty pressure points

Tire pressure, or a lack thereof, can be a significant driver of overall fuel consumption. In fact, research from NACFE reveals that a 0.5-1.0% increase in fuel consumption is seen in vehicles running with tires underinflated by just 10 PSI. It is important to note the council also found about one in five trailers are

Managing wheel-end PMs to reduce unforeseen service events

Trailer service pop quiz: Do you consider inspections “maintenance”? Answer: Maybe you should, according to Greg Dvorchak, Engineering Supervisor – Brake and Wheel-End Division, Hendrickson. “Inspection is maintenance,” says Dvorchak. From his perspective, service needs and preventive maintenance are two different things. Preventive maintenance is done to extend intervals between service or avoid unplanned wheel-end

Behind the Wheel: Uncovering the Rigorous Testing Process for Commercial Vehicle Safety Equipment

Ensuring the safety of commercial vehicles is paramount in the transportation industry. With driver safety and durable equipment in mind, leading electronic equipment manufacturer ASA Electronics has implemented a meticulous and rigorous testing process for its safety systems. The testing process adheres to the DOT, SAE, and ISO industry standards, constantly updating safety systems to