What’s that metal thing hanging from under the car?

Owning a car can sometimes invoke a lot of curiosity. This is especially true when you notice something in your automobile that you can’t explain what it is.

You may wonder what that is, whether it has any implications for your car or not, or have a pertinent question regarding it in your mind.

For example, a common question I’ve seen posed on many car forums online by curious car owners is: what is that metal thing hanging from under the car?

That metal thing hanging from under the car is usually an exhaust heat shield that has partially detached from the exhaust system located underneath the car.

It’s worth noting that cars have varying numbers of heat shields underneath them, depending on the size and power of the car, among other factors.

For example, you’ll find that some automobiles have only two heat shields, whereas others have up to thirty heat shields.

What Is An Exhaust Heat Shield Used For?

In cars, the exhaust heat shield is used for thermal management. Functioning as a thermal barrier, the shield keeps the exhaust system from overheating the floorboards and other adjacent car parts.

In addition to that, it protects flammable items that might come into contact with the underside of your car from incendiary temperatures.

As you can see, a heat shield is a critical component used to prevent a car from going up in flames due to overheating.

What Are Exhaust Heat Shields Made Of?

Car exhaust heat shields can be made from different materials, including aluminum, solid steel, thermal textiles, and high-temperature fabrics such as silica or fiberglass with proprietary coatings.

However, manufacturers prefer aluminum because it’s lighter than the rest hence a perfect choice for optimal aerodynamics. They also love this material because it’s easier to form and fabricate than the rest, easing their work.

What Causes Exhaust Heat Shields to Hang From Underneath Cars?

The heat shields are typically affixed to the exhaust system through a series of flanges and fasteners consisting of nuts, bolts, or rivets.

Over time, the fasteners may become loose due to many factors, including corrosion, frequent shaking of the car due to frequently driving on bumpy roads, and regular vibration of the car due to a long-term mechanical problem.

When some fasteners fall off of the affected area, the heat shield will detach from the exhaust pipe such that you’ll have a heat shield that’s partially attached to the pipe or hanging from under the car.

How Do You Prevent Your Heat Shields From Hanging From Underneath Your Car?

There are a few steps you can take to ensure that your heat shields won’t hang from your exhaust system. The first step is to always re-tighten the fasteners that fasten the shields to the exhaust pipe routinely.

You can check the status of your fasteners after every six months or so and do the needful. The second step is to avoid driving on bumpy roads.

If you can’t, make sure to check and re-tighten the fasteners affixing the heat shields to your car after every few drives. The third step is to lubricate your fasteners and heat seals frequently to prevent corrosion.

Last but not least, be sure to fix your car’s shaking or vibration problem if there’s one. This will ensure the car drives smoothly without unnecessarily shaking or vibrating, which could otherwise loosen the fasteners.


Is a metal thing hanging from under your car? If yes, don’t be alarmed because that’s probably just a heat shield that has partially detached from the exhaust pipe.

What you should do in this case is to reattach it back to the car. You can take your car to your mechanic to do this for you if you are not mechanically savvy or if you lack the required tools to get the job done.

Notably, there are many precautionary steps you can take to prevent your heat shields from detaching from your car’s exhaust system. One, routinely check and correct the status of your heat shield fasteners if need be.

Two, avoid bumpy roads or re-fasten your shields back into place after every few drives that may have loosened them up a little bit.

Three, fix any mechanical problem that may be causing vibration or shaking that could be loosening the heat shield fasteners whenever the car is moving.

Last, but not least, frequently lubricate your heat shields and fasteners with a high heat lubricant to prevent corrosion that could otherwise cause them to partially or fully detach from the exhaust system.

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