Whirring Noise After Engine Off: Causes & Solutions

In-depth Discussion on Reasons for Producing Whirring Sound

As mentioned earlier, the prime cause of the generation of whirring noise after engine off is the coolant fan’s functional issue. There are several other issues associated with this problem. Let’s break down the causes and get their potential solutions to address the causes efficiently.

1.     Worn-Out Cooling Fan

Automotive manufacturers incorporate a feature in their vehicle designs where the cooling fan continues running briefly even after the engine has been switched off. The reason behind this design solution is to speed up the cooling process of the engine after you have completed your journey.

The cooling fan consists of bearings like every other fan component to ensure rotation. However, when the fan’s bearings have deteriorated or the fan motor is experiencing issues, it generates a whirring noise.

Nevertheless, when components within the cooling system begin to wear down or fail. Following this, the intended tranquility post-engine shutdown is disrupted by an unwanted whirring sound.

Additionally, a malfunctioning fan motor can struggle to function smoothly, further contributing to the audible disturbance.

How to Solve?

Below is the stepwise guideline to get rid of worn-out bearings and coil parts.

• Step 01: Identify the fan under the hood.
• Step 02: Use a 10-millimeter socket wrench to take out the set of two 10-millimeter bolts on the top side. Do the right side first, then go for the left side.
• Step 03: Now, it is time to unsnap the electric connector. We strongly advise you to use electric-shock protective gloves. Just do it smoothly: take out the plug with a real squeeze with your thumb and then pull it. Then, with a little wiggling, take it out.
• Step 04: Use both hands and take out the whole fan unit.
• Step 05: You will see a screw jointing the fan-blade set up with the machine unit. Unscrew that.
• Step 06: Then unscrew the motor from the frame. Depending on car type, the screw number can vary from 2-4.
• Step 07: Now, use a flat screwdriver’s head to remove the upper portion. And take out the wire coil.
• Step 08: Hit the bearing holding plate to take it out. As it is worn out, hard-hitting is needed to take it out. Now, use lubrication throughout the bearing setting surface. And install a new bearing.
• Step 09: So, now the bearing issue is solved. Just check the coil portion for any issues. If the motor’s coil is also worn out, change the coil.
• Step 10: Reassemble the whole setup by following the process in the reverse order. Hopefully, the whirring noise is now gone.

Interested in more about Engine Problems? Here's an article you might find helpful. Why Does Misfire Happen When Starting A Car? Let’s Find Out!

2.     Car Alternator Bearing Issue

A typical indication of a malfunctioning alternator is the emission of a shrill, high-frequency whistling or humming sound, i.e., a whirring sound. This audible disturbance usually arises from the deterioration of the alternator’s bearings.

As these bearings degrade over time, they can generate whirring noise. Additionally, it’s possible to detect clicking sounds as well.

How to Solve?

Here is the resolution process for repairing the alternator’s bearing issue.

• Step 01: Shut off the car engine. Locate the alternator bearing at the Alternator itself in the engine bay.
• Step 02: Disconnect the battery to avoid receiving any shock.
• Step 03: Remove all the joining components, like bolts, clips, etc., to take out the old bearing.
• Step 04: Now, use a specialized tool named “Alternator Bearing Puller” to test the worn-out condition of the bearing.
• Step 05: If the test says that the bearing is gone, replace it with a new one. Use a torque wrench to fix it properly. Ensure appropriate tightening. Over-tightening can damage the bearing when it will work.
• Step 06: Provide battery connection and check the active voltage to ensure its functionality.
• Step 07: The whirring sound is now gone if the Alternator bearing was the issue.

3.     An issue with the Power Steering Pump

The power steering pump is a critical component of your car’s steering system. It helps to make it easier to turn the steering wheel by using hydraulic pressure.

The pump can fail due to inadequate fluid, fluid leak, contaminated fluid, snapped belt, or excessive wear and tear. You can prevent the pump from failing by checking the power steering fluid level regularly, inspecting the fluid for contamination, looking for signs of leaks, and inspecting the belt.

How to Solve?

The following is the replacement process of damaged parts of the power steering system.

• Step 01: Make sure the fluid level is at the recommended level. If it is low, add more fluid.
• Step 02: Check the fluid color. The fluid should be amber or light pink. If it is brown or dark, flush the system and replace the fluid.
• Step 03: Inspect the hoses, belts, and other parts for wear or damage. Replace any damaged parts. This kind of replacement requires professional knowledge and skills. Also, the DIY method can damage the whole setup, wasting the money.

We strongly suggest you get professional assistance in the case of the replacement of any of the items.

Watch this YouTube video to learn more about power steering pump leaking and repair.

Discover more interesting content on Engine Problems by reading this post. Why Does Your Car’s Engine Misfire At Idle? Let’s Find Out!

4.     Water Pump Issue

The whirring noise can be caused by the faulty water pump. This pump moves a special liquid around the engine. When it’s not working well, it can make a high-pitched humming/whirring sound.

Remember, these are just some possible reasons, and the real problem can be different depending on the type of car you have and how it’s doing. The main thing is to listen carefully to your car and try to find where the sound is coming from if you can.

How to Solve?

Below is the step-by-step guide to solve the leakage in the water pump.

• Step 01: Usually, you’ll locate the water pump near the front of the engine block.
• Step 02: Examine the area around the water pump for any signs of leaks.
• Step 03: If you observe a leak, this could be the source of the whirring noise you’re hearing.
• Step 04: In the event of a leak around the water pump, it may be necessary to replace the pump to address the issue.

People Also Ask

Now that you know about the issues and how to solve them. Here are answers to some of the most common questions people have regarding the matter!

How long does the whirring noise last after shutting off the engine?

The duration of the whirring noise can vary. In general, it lasts for a few minutes. It depends on the specific vehicle and how hot the engine is at the time of shutdown.

What to do if warning lights accompany whirring noise?

If the whirring noise is coupled with warning lights, just be calm and stop the vehicle on the side of the road. It is for sure that there is a major problem which needs to be resolved before starting again.

Is it safe to ignore a whirring noise that occurs only briefly after shutting off the engine?

If the noise is brief and occurs only a few times, then it is fine. But, if it is consistent with normal cooling processes, and the noise lasts for an extended period, You cannot ignore the case.

Final Words

Whirring noises occurring after turning off a car’s engine are not a normal part of the vehicle’s cooling and post-shutdown processes. We hope that our elaboration on the whirring noise after the engine is off has made you understand the reasons and resolutions.

We suggest you immediately take action: check the cooling fan condition, alternator’s bearing, water pump condition, etc. If you find any problem, apply the above-mentioned approaches to resolve the issues. If you are not familiar with handling such mechanical issues, please, take professional help.