Car Makes Whirring Noise When Slowing Down! 6 Causes and Their Fixes

Car Makes Whirring Noise When Slowing Down- 6 Reasons and Solutions Discussed

Know why these problems occur and how to deal with them.

1. Bad Water Pump

The water pump pumps the coolant into engine components. If the water pump fails to circulate the coolant efficiently, the engine will heat up. This may create a gaseous state inside the cooling system, and coolants returning to the reservoir will make a whirring noise.

If the whirring noise comes from the front of your car, chances are the water pump is faulty. There can also be leaks in the water pump that cause air to build up inside the system. As a result, you will hear a whirring noise while slowing the car down. Damaged or worn water pump pulleys can also create this noise.

How to Fix This?

1. Park the car in a leveled place and place a large cardboard below the engine block. If there are signs of wetness, there can be leaks in the water pump.
2. Check if the water pump pulleys are worn or damaged. If so, replace the pulley with a new one.
3. If everything else is okay, but the noise is persistent, you should take the vehicle to a repair shop and get the water pump replaced. It will cost about $500, including parts and labor.

2. Bad Fuel Pump

The fuel pump delivers fuel to the engine at the right pressure. If the fuel pump is at fault, it won’t be able to generate the pressure. The low pressure of fuel will cause a loss of power. You will feel that the vehicle isn’t slower than before.

And when you decelerate, a whirring noise will come from the engine. Low-pressure fuel inside the system causes this noise.

How to Fix This?

1. You should take the vehicle to a repair shop for a fuel pump inspection. If the pump appears to be faulty, get it replaced. It may cost about $400-$600, including parts and labor.

3. Clogged Fuel Filter

Fuel filters ensure only clean fuel reaches the engine. Over time, debris accumulated on the filter clogs the filter. So, it can’t provide enough fuel to the engine. As a result, the engine will lose power. And when the vehicle slows down, you will hear a whirring noise.

How to Fix This?

1. The first step is to take the fuel filter out. Carefully reach the bottom of the car and remove the fuel filter.
2. If it is slightly dirty, you can clean the fuel filter and reuse it.
3. But if the fuel filter is too dirty or clogged, you should replace it. You may get a new fuel filter at under $100.

4. Cracked Driveshaft Boots

Driveshafts have rubber boots near the joints. If these boots get cracked, they will make a whirring noise when the rotation speed of the shaft varies. For example, if the vehicle is running at a constant speed, there won’t be any noise.

When you slow down, the difference in speed will cause the cracked boots to flap. As a result, you will get a whirring noise from the car. Worn U-joints in the driveshaft can make driveshaft noise when decelerating.

How to Fix This?

1. You should visually inspect the driveshaft boots first. Rotate the boots all the way around and check for signs of cracks or tears.
2. If the boot is cracked or torn, replace it with new boots. It will cost about $50-$100.
3. Also, check the U-joints for signs of wear. If the joints are worn, take the vehicle to a repair shop and get the driveshaft replaced. It may cost about $500-$1,500, including parts and labor.

5. Low Transmission Fluid

The components of your car’s transmission should be lubricated well to perform smoothly. If the transmission fluid level is low, the components will start making a whirring noise. It is more prominent when you slow the car down. Transmission fluid performance also impacts the fuel economy of the car.

How to Fix This?

1. Remove the transmission fluid reservoir cap and take the dipstick out.
2. There might be MIN and MAX markings on the dipstick. The fluid level should be close to the MAX level at any time.
3. If the fluid mark is near the MIN level, you should refill the transmission fluid.

6. Low Tire Pressure or Worn Tires

Maintaining optimal tire pressure isn’t only important for improved performance and fuel efficiency, but it also prevents unwanted noise. If the tire pressure is low, the tires will make a whirring noise, especially when slowing down.

Sometimes, tires can be too old, and their treads can be worn. That is also a common cause behind the whirring noise from your car.

How to Fix This?

1. The first thing is to check the tire pressure. If you have a TPMS or tire pressure monitoring system in your car, you will get the reading on the display. But if not, you need to use a pressure gauge to check the pressure in all tires manually.
2. If the tire pressure is low, inflate the tires to the recommended level. Most vehicles need about 35 psi of air pressure.
3. Inspect the tread patterns for signs of wear. If the tread depth is too low, it is time to replace the tires. Replacing each tire will cost about $150, including cost and labor.

Why does a car make a popping noise when slowing down?

When a car makes a popping noise when slowing down, it’s a fascinating result of fuel igniting in the exhaust system.

This distinctive sound occurs during downshifting and engine braking, a process that creates an exceptionally lean mixture in the cylinders. The lean mixture, too thin to ignite by the spark plugs, finds its combustion moment in the exhaust.

This phenomenon is universal across engines, whether fuel-injected or not. Even though fuel injection systems shut off injectors during deceleration, remnants of the mixture persist in the cylinders.

Most cars, however, remain discreet about these crackling sounds due to efficient muffling through catalytic converters, resonators, and mufflers. Remove those, and many cars will reveal their inherent tendency to crack and pop.

If your vehicle is producing whirring noises when decelerating, you may find our guide on ‘Whirring Noise After Engine Off: Causes & Solutions’ insightful in comprehending all potential factors contributing to the sound and gaining insights into diagnosing and rectifying them. This resource is your comprehensive solution hub. Whirring noise after the engine is off offers a detailed examination of the prevalent causes behind your car’s whirring noise post-engine shutdown and effective troubleshooting methods. Meanwhile, our article on whirring noise while driving delves into everything you need to know about tackling this issue.

FAQs

Many car owners also ask these questions regarding the whirring noise when slowing down. Check the answers to these questions.

Q: What causes the noise when decelerating in gear?

If your car makes noise when you are decelerating and still in gear, the problem is probably with the transmission system. Without enough lubrication, the gears can make noise. The gears can also be worn.

Q: Do new cars make a whirring noise when slowing down?

New cars aren’t supposed to make any noise due to worn or faulty components. But if the transmission fluid or tire pressure is low, even new cars will make a whirring noise.

Q: Can I drive a car with a whirring noise when decelerating?

You can, but that drive should only be to a repair shop. Driving a car that makes noise when slowing down for a long time can further damage the components.

Final Words

I like to think of car noises as labeled because they always give hints about what component could possibly be bad. Take the whirring noise, for example. If your car makes a whirring noise when slowing down, chances are any one of the above reasons is present.

Your job is to promptly identify the reason and take steps accordingly. Stick to the standard maintenance schedule to keep tire pressure, transmission fluid, etc., at optimal levels. And check components for physical damage to prevent the whirring noise while decelerating.