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Pool Pump Making Grinding Noise? Here’s Why (+ How to Fix)

A grinding pool pump motor is a definite cause for concern. These unsettling sounds often indicate an internal issue that could overheat and ruin the motor.

Not only does it create a loud noise that nobody wants to hear, but it can also damage the filter, heater, plumbing, and other pieces of equipment.

A pool pump makes grinding noises because of the following reasons:

  1. Clogged pool pump
  2. Broken suction valve
  3. Severely damaged motor bearings
  4. Dirty pool vacuum

In this article, I’ll explain all of the possible reasons your pump is making those unwanted grinding noises. I’ll also walk you through what you can do to fix each issue and prevent them from returning. Let’s get started!

1. Clogged Pool Pump

If the pump is clogged, you’ll hear all sorts of rattling, grinding, humming, and more.

Your pool pump has three locations that can get clogged:

  1. Pump basket
  2. Impeller
  3. Unions

Clogs in any of these areas will negatively affect the pump’s performance, dropping the water flow and overheating the motor.

How To Fix

Unclogging the pump will fix these issues. Below, we’ll discuss how you can clean the whole pump.

  • Clean the impeller. Turn off the pump, remove the lid, and use a screwdriver to remove the excess debris behind the basket.
  • Dump the pump and skimmer baskets several times per week. Always turn off the pump before emptying the baskets since they suction to the skimmer and pump when the water is moving.
  • Loosen the unions before and after the pump, then remove the excess gunk. The unions trap a lot of debris because they’re the chokepoints between the pump and the filter.

2. Broken Suction Valve

Suction valves refer to any valve before the pump’s inlet. These valves decide where the pump pulls water from, including the spa, pool, or vacuum.

A broken valve flap will grind and vibrate until the screws and flaps fall out of the valve, damaging the plumbing. Misaligned valve flaps can also narrow the water flow.

How To Fix

To repair a broken suction valve, follow these steps:

  1. Turn off the power to the pump.
  2. Remove the valve’s lid with a screwdriver (there should be between four to eight screws).
  3. Pull out the internal parts (also known as the valve guts).
  4. Replace the internal parts with a like-for-like part number provided by the manufacturer.
  5. Seal the valve’s lid with the retaining screws and turn on the pump’s power.

3. Severely Damaged Motor Bearings

Damaged motor bearings are the most common cause of grinding noises from a pool pump. The bearings have to be quite rusted and corroded to grind.

They usually start with a humming sound or hissing sound. The corrosion worsens from the stripped bearings, which eventually causes the aforementioned grinding noise.

How To Fix

Worn bearings overheat many other internal parts, which means the motor almost always needs to be replaced. Once you have a new motor, you can follow this procedure to fix the issue:

  1. Turn off the pump’s power.
  2. Remove the screws between the housing and the motor.
  3. Remove the impeller with a Phillips screwdriver.
  4. Disconnect the motor’s wires, then connect them to the new motor.
  5. Attach the impeller to the new motor.
  6. Connect the motor to the housing.
  7. Prime the pump and open the filter’s air relief valve to remove the air bubbles.

4. Dirty Pool Vacuum

A clogged or filled pool vacuum will change your pump’s performance. It’s important to empty the vacuum and look for damaged components.

A dirty pool vacuum is one of the many reasons your pump isn’t pulling water.

It can also cause a grinding noise because the pump can’t pull as much water as it should. This process can overheat the motor.

How To Fix

Here’s what I suggest:

  • Turn off the pump, disconnect the vacuum, and remove all of the debris from the pump’s basket.
  • Remove the debris from the vacuum’s bag (this step isn’t applicable if you have a suction-side vacuum since the debris goes into the pump’s basket).
  • Use a garden hose and a toothpick to clear out the debris from the vacuum’s hose assembly if you have a pressure-side vacuum.
  • Inspect and replace the vacuum’s wheels and feet if necessary.
  • Spray a garden hose through the vacuum’s hose to remove excess debris clogs.

Pool Pump Noise Troubleshooting Resources

If your pump is making any other noises, our other pool pump noise troubleshooting articles may be able to help:

Author

  • Jonah Ryan

    Jonah has worked for several years in the swimming pool industry installing and repairing equipment, treating pools with chemicals, and fixing damaged liners. He also has plumbing and electrical experience with air conditioning, ceiling fans, boilers, and more. When he's not writing for Temperature Master, he's usually writing for his own websites, LawnCareLessons.com and DIYByHand.com.

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