Repair & Maintenance

What is Causing the Grinding Noise Under My Car?


Listen up!


Full of moving parts, your vehicle is a symphony of sounds and movement. From the roar of the engine when you start it to the sound your anti-lock brakes make, you know what noises are normal for your car and what sounds are out of the ordinary. Strange noises are your car’s way of telling you that something is wrong and needs attention.

When you start hearing an unusual grinding noise coming from under your vehicle, you know it’s time to pay attention. Grinding noises are associated with rotating parts and rotating systems. Any part or system that rotates can cause grinding. If your car starts making grinding noises, don’t wait to get it checked out, get it taken care of before it turns into a bigger issue.

Top causes of grinding noises under your car


The two most common causes of grinding noises under your car are worn brake linings or failing wheel or hub bearings. Whichever action creates the grinding noise is the affected system that needs repair.

How your brakes can cause a grinding noise


Disc brake pads and drum brake shoes are a frequent contributor to grinding noises. Grinding noises appear when the brake friction material or brake linings have worn away and the steel brake rotor is rubbing against the metal brake pad backing. This causes metal-to-metal contact when the brakes are applied, creating a grinding noise.

This grinding is generally a very loud noise and will only grind when your brakes are applied, making the diagnosis very simple. Typically, the grinding noise will come from either the front or rear brakes, but not generally both. The repair for grinding brakes is simply a brake job or brake overhaul on the affected set of pads.

How your wheel/hub bearings can make a grinding noise


Designed to serve as a buffer between the axle and wheel, wheel or hub bearings eliminate friction between these parts. If your wheel bearings are worn, it can cause a grinding noise while turning the vehicle. Poor steering and handling and uneven tire wear are just some of the effects of failing wheel bearings.

Other culprits

If the brakes or wheel/hub bearings aren’t causing the grinding noises, it’s time to explore other parts that could be the source of your issues. 


Water pump – A failing water pump can causes a grinding noise while the engine is running. Without a fully functioning water pump, your car can overheat. If you suspect that your water pump is failing, schedule an appointment with your mechanic before further damage is done to your vehicle.


CV joint – A worn CV (constant velocity) joint can cause your vehicle to make grinding noises when making tight turns at slow speeds. Left unattended, a damaged CV joint can fail, leaving you with a vehicle that is stuck in park. If it fails while you’re driving, it can lead to a loss of control. Don’t waste any time in getting your vehicle in to your mechanic if you think this is the cause of your grinding noises. 


Alternator – Grinding noises can also be a sign that the alternator is wearing out. Modern alternators have a decoupler pulley system that helps save fuel but can make a grinding noise that is hard to find. Designed to charge your car’s battery and power the electrical system, a failing alternator can leave you on the side of the road with a dead battery.


Air conditioning – AC compressors can also be a source of a grinding noise. You may only notice it when your air conditioning system is on. Be sure to get it fixed since it not only keeps you cool in hot weather but it also helps remove moisture from your windows in the winter.

Learn more about quality auto parts, find your car part, or find a local car repair shop today.

The content contained in this article is for entertainment and informational purposes only and should not be used in lieu of seeking professional advice from a certified technician or mechanic. We encourage you to consult with a certified technician or mechanic if you have specific questions or concerns relating to any of the topics covered herein. Under no circumstances will we be liable for any loss or damage caused by your reliance on any content.

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