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Car Shakes When AC Is On – DIY Troubleshoot

Car Shakes When AC Is On
Written by Nick Steiner

If your car is shaking when you turn the AC on then, you have a problem. This can indicate a problem with the AC compressor, which is common.

Several other issues can cause the car to shake when the AC is on, which we will discuss below.

What Makes the Car Shake When You Turn the AC On?

What Makes the Car Shake When You Turn the AC On

1. High pressured AC compressor

The car’s compressor adds a big strain to the vehicle’s engine. If you have pressure rising above 400 PSI, you are going to get vibrations. If the pressure is still able to increase, engine parts will start wearing out.

2. Damaged AC compressor

A faulty AC compressor adds pressure to the vehicle’s engine, and this can create vibrations. Therefore, a damaged AC compressor will not function properly.

The compressor cools the refrigerant before it sends it to the condenser. If the AC compressor malfunctions, then it will cause the car to shake when it is idle, and the AC is on.

3. No airflow in the throttle body

The throttle body works to maintain the airflow within the engine. When the throttle body and the mass airflow sensor are dirty, it will run rich or lean. This will cause the car to run rough or backfire.

Once you turn the AC on, you will feel the car start to shake. The only way to fix this is to clean the throttle body and the airflow sensor.

4. Overloaded engine

When the air conditioner is turned on, the air control motor and the idle speed become activated.

Due to the high-tech insulation, the compressor puts too much strain on the engine, resulting in vehicle shaking once a load has risen above the limit.

5. Hoses are disconnected or loose

Sometimes a shaking car can be caused by a smaller problem such as a hose that’s disconnected or one that is loose.

If the hose isn’t connected correctly, it will interrupt the flow of the car’s air conditioning system. You might experience shaking and vibrations.

6. Spark plug problems

The spark plugs work to create power for the engine. It works by the fuel and air connecting and creating an explosion. Unfortunately, outdated or damaged plugs can cause a car to vibrate when you turn on the AC.

You will need to have your spark plugs replaced to fix this problem.

7. Broken or worn motor mounts

The engine mounts work to secure the engine and suspension into place. The transmission and engine need to be secured at the right angle.

When the AC is running, it creates strain on the mounts. When they go through too much strain, they will start to wear out, creating shakes and vibrations when the AC is turned on.

8. Fuel injectors are defective

The fuel injectors are important for your vehicle. They work to spray and limit the flow of gas to your car. The injectors work with the electronic valves, so they are able to open and close.

If you are suffering from a malfunctioning fuel injector, then your engine will suffer a strain. This will cause the car to shake when the AC is switched on.

9. Faulty throttle position sensor

The position sensors work to keep track of the air intake. The sensor maintains how far the valve can open, which is controlled by how far you are pushing the gas pedal down.

If you have a faulty TPS, then the vehicle’s RPMs cannot be controlled properly, which will result in your car shaking when the AC is turned on. When the RPMs are not consistent, the car will vibrate.

What to Do When the Car Shakes After Turning the AC On?

1. Faulty suspension components and steering joints

The vibrations you are feeling may come from faulty suspension or steering joint problems due to wear and tear. These will need to be replaced or repaired as soon as possible before you go driving.

  • Pull the steering wheel fast when turning right and left ¼ of a circle. You should be able to hear knocking noises and have plenty of free play
  • If the car has power steering, do this with the car running
  • Check the pinion steering system and the steering boots for damage
  • If you can hear noises when turning, you might need a new ball joint

2. Leaks in the hoses

When you turn the AC on, you might have a hose leak if the car shakes.

  • Conduct a visual inspection to look for cracks, disconnections, or damage
  • Soapy water applied to the hoses. If there is a hole or crack, the leak will bubble up once the solution is applied
  • The ultraviolet dye can be used to find problems. Just add the dye to the refrigerant and use a UV light to locate leaks.

3. Make sure there are no missing bolts or screws

  • Locate all the screws and bolts under the hood
  • Give them a fiddle and see if any are loose
  • Loose bolts or screws that are found can be re-tightened with the right tool

4. Check for strange noises

Strange noises within the AC system can be caused by different things:

    • Check your fixing points and clamps to ensure they are intact without missing screws and breaks
    • Hold your lines and hoses with your hands to see if the noise stops indicating the vibrations are being sent to the vehicle’s cabin.
    • If there is a problem with the air-con compressor belt, clutch, tension pulleys, or clamping device, you might experience strange noises

5. Check for fins on the engine compressor

  • Check the fins to see if there is damage or scratches on the fins
  • Use an emery cloth or fine sandpaper to gently sand over the scratches or dents.
  • A fingernail file can also be used to fix any rough edges.

6. Seek help from a professional mechanic

If you are unfamiliar with the car’s AC system mechanism or don’t have any experience in finding problems and fixing them yourself, take your car to a professional.

If you have doubts about your skills or using the correct tools, a mechanic can look over your car, find the problem, and repair or replace the items usually the same day.

  • Contact a trusted mechanic
  • They will book you in for a time and date that suits you
  • You will receive a call when the car is fixed and ready to pick up

7. Get help from others and use the right tools

You can risk injury to yourself if you are trying to juggle too many things under the hood. Having enough hands to help hold tools and parts while working on them will make the job easier and safer. It is important to use the correct tools to avoid damaging any of the car parts.

  • Look in your manual or online to check what tools are needed
  • Have someone around to help hold or use the tools

FAQs

1. Can a bad AC compressor damage the engine?

Ans. A bad compressor can cause problems for the engine. For example, your engine will stall if a compressor’s pulley fails or the compressor becomes stuck or if your serpentine belt breaks, which will cause problems for the parts controlled by the belt.

2. Is it safe to drive when your car is shaking?

Ans. It isn’t just annoying but driving when your vehicle is shaking is unsafe. Whatever the problem is, you need to get it fixed asap. Driving with a shaking vehicle can cause you to crash the vehicle and injure yourself or others.

About the author

Nick Steiner

Nick has been a car nut for his whole life as far as he can remember. His father was a car dealer who used to change and repair his cars himself. As a result, Nick had the opportunity to get around all sorts of cars and learned to get his hands dirty repairing vehicles from an early age.

Nick is a great fan of Japanese quality and German preciosity. His deep passion lies in older models that he believes have a flair that takes him back to his childhood. He also loves their durability and reliability when compared to the modern models.

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