Why Is My Car Amp Overheating?


If you have a powerful car amplifier installed, there is a chance it will overheat.

I went through this several times, so I decided to put facts together and write this article about why car amps are overheating and what to do about this issue.

As a general rule, car amplifiers overheat due to bad wiring, or lack of ventilation in the car, especially when powerful amplifiers are placed in closed trunks. Another common reason for car amplifiers to overheat is not matching impedance with the speakers or when the installed amplifier does not have enough power.

As an Amazon Associate, ImproveCarAudio will receive a small commission from qualifying purchases made through the links in this article.

Tip: Properly designed car audio installation can reduce or completely remove the risk of an overheated amplifier, however using the wrong size ground wires may cause it to overheat and shut off.

To ensure that wires will be 100% accurate for your power, I recommend purchasing a ready-made wiring kit that contains all necessary cables, connectors, and fuse holders.

The best kit I have found is a gauge 4 KnuKonceptz Kolossus OFC which can support a single amplifier up to 1,800 Watt RMS.

In this article, you will find more details about the signs of overheated amplifiers and how to stop this from happening again.

Why Does My Amp Overheat?

High-quality amplifiers are less likely to overheat, so saving money on the amplifiers is not always a good idea. However, if you are on the budget, it is better to have strong quality speakers powered by radio than have them connected to a mediocre amplifier.

We can expect the best and the most expensive amplifiers like JBL, JL Audio, or Infinity to work for a long time in various conditions because they are designed to use the electrical power coming from the alternator or battery in the most effective way.

The quality of the amplifier is not the only reason for the amp to overheat, and although some expensive models can produce a lot of heat, it is done by their design.

For example, “A class” amplifiers create a lot of heat, but this is how they work, which does not mean it has been damaged.

What Causes an Amp to Overheat?

There are a few reasons why your amp might be overheating. The most common issues that cause this problem include:

Shorted Speakers in Car

If one of your car speakers is “blown” or grounded to the vehicle’s chassis, the amplifier will still power it, and when it does, it gets hot quickly and shuts down.

Bad Ground or Power Connection

Bad connection and especially bad ground can cause an amp to overheat. If you are using ground or power wires too small for your amplifier (too thin), the amp can overheat and shut down because it is not receiving sufficient power to make the output you want.

For most car amps, you should use at least 8-gauge power and ground cable for each installed amp. Both ground and power wires should be the same size and run directly from the battery to the amplifier.

Lower Impedance Than Amp Can Handle

When you use one or more woofers whose total load is lower than the amplifier has been designed to work with, it may overheat shut down to protect itself.

This is the most common mistake when connecting two 4 Ohm woofers in parallel for a 2 Ohm load and then bridging the 4 ohm amp to the 2 ohm load.

If your amp is not prepared to work with a low impedance of 2 ohms, it will heat up due to the extra power needed that it cannot make, and once it gets too hot, it shuts down, or it turns off to protection mode.

Gain & Bass Boost Set Too High

Gain and the bass control settings are the simplest to check when your amp keeps overheating.

The gain control tells the amp how much power you want it to produce, and if you have the gain set too high, the amp will try to make full power right away.

In effect, you will have problems with sound distortion and clipping of an overheated amp.

On the other hand, If the gain is set too low, the amp will still make full power, but it might not sound as loud as it should. 

The Amp Is Not Strong Enough for Speakers

If an amplifier cannot produce enough power for the demanding speakers, it will quickly overheat. Powerful speakers need to receive sufficient energy, especially at a high volume.

Amplifier Does Not Have Sufficient Ventilation

If your amp does not have enough ventilation, it can overheat, and in effect, it can switch to protection mode or completely shut down.

Most ventilation issues are temporary, which means that the amp keeps overheating and turns back on after cooled down. However, when your amp overheats often, it can face permanent damage.

Some amplifiers like MTX JackHammer JH600 are equipped with active cooling fans, so it can be a good option if you do not have much free space in the car and want to prevent the amp from overheating in the trunk.

What Are the Amp Overheating Symptoms?

The most visible symptom of the overheated amp is when it is going into protection mode.

Protection mode means that the amplifier shuts down to prevent further internal damage. Protect mode also prevents damage to other car audio components, like wiring or radio.

When your amplifier shuts down after some time, it is usually caused by the heat, but it also can be caused by wiring problems if it happens right after turning the radio on.

Although the amplifier in the protect mode can cause your headache, do not worry. Regardless of the reason, you have to investigate it and remove the cause if you want to enjoy your favorite music again.

Below are other signs of overheating amplifiers:

  • Clipping
  • unstable functioning
  • constant turning on and off
  • noise
  • not turning on at all
  • smoke
  • fire

What to Do When My Amp Is Overheating?

If you notice that the amplifier is overheating, shut it off right away to avoid further damage.

Regardless of what causes an amp to overheat, you have to find a reason and stop it from happening again. Otherwise, you may risk severe damage to the car sound system or even a car.

Although an overheating amp will shut down and go to the protect mode in most cases, it is crucial to ensure the car audio installation is safe.

How to Keep Amp From Overheating?

Below are a few simple steps to prevent the amplifier from overheating:

Use Reasonable Volume

The simplest preventative measure is volume control. Too much energy produces heat and can overheat your amp. Neither amplifiers nor speakers are made to work at the highest volume for a long time. 

Install a High-Quality Amplifier

Mediocre amplifiers are more likely to overheat than branded ones, so investing in a good amplifier will save you from overheating issues.

When searching for the amplifier, pay attention to its class. There are four main amplifier classes that refer to power, sound quality, and efficiency.

  • Class A amplifiers create the highest sound quality, but they are least efficient, therefore, produce the highest amount of heat. They are excellent for the audiophile car audio systems, where sound quality is the only priority. A class amps are not popular in car sound systems.
  • Class B amplifiers are more efficient than A, but produced sounds have more distortion. B class amplifiers are also not often visible in cars.
  • Class AB amplifiers combine the A and B classes, and their design offers power efficiency and excellent sound quality. When you value the quality of your favorite tracks, AB amplifiers are the best choice to power car speakers. They produce a reasonable amount of heat and are often used to power car speakers.
  • Class D amplifiers are the most popular in car audio systems. They are the most efficient of all classes and produce nearly no heat. However, the signals they offer are of low quality. Thanks to the amount of power they make, D class amplifiers are excellent for subwoofers in the vast majority of the sound systems.

Ensure Amplifier Has Good Ventilation

When installing an amplifier, try to find a location surrounded by free air to prevent the amp from overheating and cutting out.

To increase airflow around the amplifier, avoid installing it in the trunk’s tight spots. Instead, make sure the air gaps between the top, bottom, and sides of the amp are large enough for unrestricted airflow.

In some cases, you may need to add adaptor plates between the bottom of the amplifier and the mounting surface to increase the air gap.

It can be handy to add between the amp and the mounting surface ¼” pieces of wood or plastic. Adding them just underneath the bolting holes increases the air gap significantly.

Install Amplifier Cooling Fan

Even if you installed the amp in a well-ventilated location, you still might have an overheating problem. If the amplifier needs more fresh air, you may need to install an amp cooling fan.

Many fans can be powered by 12V, and their installation is straightforward. You can install it next to the amplifier, and it will blow the heat away, keeping the amp running as it should.

A good example is the Stinger SGJ78 8.25-Inch Cross-Flow Fan, which, placed next to the amp, blows the cool air on top of the metal amp’s body.

You can bolt it down through four bolt holes next to the amplifier, and it is ready to work. Wiring is also straightforward, and the whole installation does not take more than 15 minutes.

Make Sure Amp’s Impedance Matches the Speakers.

Impedance is the amount of electrical resistance, which speakers create against an amplifier’s output. The lower the impedance, the higher the amplifier has to work.

The most common impedance in the car audio is 4 Ohm, but some speakers work with a low 2 ohm impedance.

The lowest impedance used in the car audio is 1 ohm, but this is only used for the strongest subwoofers, for example, Skar Audio ZVX-12v2 D1.

Regardless of which impedance your speakers work, make sure your amp can support it.

Otherwise, after pairing 2 ohm speakers with a 4 ohm amplifier, you may find out that your system does not work and your amp keeps overheating and cutting out.

This is because 2 ohm speakers overload the weaker amplifier and cause it to overheat and shut down.

Ensure Your Speakers Are Not Blown or Shorted

Speakers that are blown or when their loose wires touch your car’s chassis will cause an amp to overheat and cut out.

Damaged speakers or those with bad connections are easy to find because faulty speakers will either stop working or create distorted sounds.

If the amplifier overheats after running for a while, check if speakers are not blown and wires are safe in the terminals.

Make Sure the Amplifier Has a Good Ground Connection

The improper ground connection does not only cause overheating of car amplifiers but can also cause fuses to blow or create shorts.

If you want your amplifier to work efficiently, you must ensure the black (negative) wire has a stable connection with the vehicle’s chassis.

When the ground connection is poor, the amp may overheat right after turning on, fail to turn on, or even not work at all, so check the ground connection point and clean and tighten the bolt if required.

Before bolting the ground wire, remember to remove any paint from the grounding point. The ground wire connection should only touch the bare metal of the vehicle’s chassis.

Check the Size of the Power and Ground Wire.

A stable connection of the amplifier to the ground and battery is not everything.

You have to make sure you use the wires of the correct size (gauge), especially when installing a strong subwoofer.

Using the wrong size power or ground wires may cause an amp to overheat and shut down because the amp does not receive enough energy to work correctly.

When installing a new amplifier and ensuring that wires will be 100% accurate for your power, I recommend purchasing a ready-made wiring kit that contains all necessary cables, connectors, and fuse holders that you will need for the amplifier.

The best quality kit I have found, and I already bought two, is KnuKonceptz Kolossus OFC Installation Kit which supports an amplifier up to 150A, or 1,800 Watt RMS. KnuKonceptz is known for the top quality of its products and uses excellent quality OFC wires. 

Adjust Bass Settings on Your Amplifier

Although adding a bass boost could increase the music’s dynamic, it can cause the amplifier to overheat and start clipping when it is set too high.

On the other hand, if the gain is set too low, the amp might not sound as loud as expected. The best way is to set the mass boost in the new amplifier at zero and slightly adjust to the level you are happy with.

If you start hearing any sound distortion or clipping of the amplifier, reduce bass by 2dB and leave it at this level.

Summary

A car amplifier can overheat for various reasons, but the most common is the lack of airflow around it when mounted in a tight spot or underneath the car seat.

Although overheating and cutting out amplifiers can seem scary, keeping a car amp cold is not as difficult as many can think.

Make sure you have enough airflow around it, your amp matches the speakers, wires are connected properly, and you will be fine.

Martin

Welcome to ImproveCarAudio! I am Martin, and I love to write about everything related to car sound systems. I strive to provide the most accurate and helpful information about car audio through extensive research, as well as my experience with car audio installations.

Related Articles