Did you ever notice that when you turn on the air conditioner (AC), your car starts to shake? If so, you’re not the only one. This is a problem that a lot of car owners have, especially when it’s hot outside. But why does this annoying sound happen, and how do you fix it?
Car vibration is when the body or parts of the body of the car shake or tremble. It could be because of a number of things, including a problem with the engine, the tyres, or the frame. However, the vibrations can sometimes be caused by the car’s AC system. It puts extra stress on the engine when the AC is on, which can make it work less well and cause vibrations.
Causes of Car Vibration When the AC is On
There are a few things that could be making the car shake when the AC is on. Here are some of them:
- Having trouble with the engine mounts? The rubber or metal parts that hold the engine in place and separate it from the chassis are called engine mounts. They keep the noises and shocks from the engine from getting to the body of the car. But the engine bolts can wear out, crack, or break over time because of heat, pressure, or rust. It’s possible for the engine to move too much when this happens, which can make the AC vibrate.
- Issues with the AC compressor: The gadget that squeezes the refrigerant gas and moves it through the AC system is called the AC compressor. It is moved by a belt that goes from the engine flywheel to it. There are many things that can go wrong with the AC compressor, such as a low amount of refrigerant, electrical problems, or damage to the machine itself. When this happens, the AC fan may make noise and shake when it turns on and off.
- Serpentine belt issues: The serpentine belt is a long rubber belt that slides along different pulleys and powers various engine parts, including the generator, power steering pump, water pump, and air conditioner compressor. An old belt, heat, or pressure can cause it to wear out, stretch, slip, or break. If this happens, the serpentine belt might shake when it spins quickly or when the force is lost.
- Problems with the pulleys: The metal wheels that move and support the serpentine belt are called pulleys. In the engine area, they are connected to different parts. Because of dirt, rust, or damage, the pulleys can break, bend, get out of place, or stop moving. In this case, the pulleys may cause vibrations if they spin incorrectly or get in the way of the serpentine belt.
- Having trouble with the idle speed? The idle speed is how fast the engine runs when it’s not working hard. The amount of air going into the engine is limited by a part called an idle air control valve (IACV). Several things, like temperature, altitude, or load, can change the idle speed. It takes more air and fuel for the engine to stay at a steady running speed when the air conditioner is on. If the IACV or other parts that affect the idle speed are broken, like spark plugs, fuel injectors, or vacuum leaks, the idle speed can drop too low or change too much, which can cause the engine to vibrate.
Solutions for a Car That Vibrates When the AC is On
If your car shakes when the air conditioner is on, you need to fix or repair the parts that are making it shake. Here are a few things that might help:
- Changing engine mounts that are old or broken: To change the engine mounts, you need to use jack stands to raise and support your car. Next, take off the bolts that connect the engine mounts to the engine block and the frame. A jack or pry bar will help you lift the engine a little and take off the old engine frames. After that, put the new engine mounts in place and tighten the bolts. Put your car down, start the engine and then check to see if the shaking is gone.
- Changing the broken AC compressor: To change the AC compressor, you need to use a recovery machine to drain and refill the refrigerant in your AC system. After that, you need to take your AC compressor’s electrical connectors and lines off. To take your AC compressor out of your car, you need to take out the bolts that hold it to its place. Then you need to put in your new AC compressor and connect its electrical wires and hoses again. You need to use a charging machine to add more gas to your AC system. Start your car’s engine and turn on the air conditioning to see if it works right and doesn’t shake.
- Changing a serpentine belt that is loose or worn out: To change the serpentine belt, open the hood and find the serpentine belt idler. The pulley that keeps the force on your serpentine belt is usually one that is loaded with springs. To release the stress in your serpentine belt, you need to turn your tensioner either clockwise or anticlockwise (depending on how it’s made). First, take off the old serpentine belt from its pulleys. Then, put on the new one by following the routing diagram, which is generally on a sticker under the hood. You need to turn your idler around and pull on your new serpentine belt. Start your car’s engine and make sure the new serpentine belt moves easily and doesn’t make noise.
- Changing out old or broken pulleys: To change the pulleys, you have to open the hood and find them. Most of the time, bolts or nuts hold them to different parts in your engine area. You will need to use a wrench or ratchet to take them off one at a time. Then, put in your new pulleys by following any adjustment marks they have and making sure they are tight. You need to turn on your engine and see if the new gears move easily and without any shaking.
- Setting the idle speed: To set the idle speed, you may need a scan tool that can talk to your car’s computer (ECU) or a knife to turn a screw on the throttle body. To get to the rest speed settings, you need to connect your scan tool to your car’s diagnostic port, which is usually under the dashboard, and then do what it says. You need to change the idle speed to the number you want (usually between 600 and 1000 RPM) and then save the changes. You can also use a screwdriver to turn a screw on your throttle body, which is generally near the air intake and controls how much air goes into the engine. You have to turn the screw either clockwise or anticlockwise until the rest speed you want is reached. After you turn on the AC and start the engine, make sure the idle speed stays fixed and doesn’t move.
Conclusion
Many car owners have trouble with their cars shaking when the air conditioning is on. Some of the things that can cause it are issues with the engine mounts, the AC compressor, the serpentine belt, the pulleys, or the idle speed. You need to look at different parts of your car for signs of damage or failure in order to figure out what’s wrong and fix it. To stop the shaking, you might have to fix or replace some of these parts.
