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Will A Bad AC Compressor Affect The Engine?

The AC compressor is one of the most important parts of a car’s air conditioning system. It is the powerhouse of the system which puts a high amount of pressure on the refrigerant and pushes it into the condenser mechanism.

The compressor is connected to the car’s engine. So, this raises a question. Will a bad ac compressor affect the engine?

If a defect is found inside the ac compressor, it won’t harm the engine. If the clutch or the accessory belt that connects the ac compressor to the engine breaks, it’ll affect the engine.

Read this article to understand the connection between a bad ac compressor and your engine in detail.

The Connection Of The AC Compressor With The Engine

A well-functioning compressor is necessary for your car’s air conditioning system to work efficiently. Your car’s AC compressor is directly connected to the engine. In modern automobiles, the pulley of the compressor is connected to the engine via an electromagnetic clutch. This clutch helps the pulley to rotate and starts the compressor when the AC is turned on.

But most recent cars are built with the ability to divert the compressor’s flow by bypassing the compressing system. But the basic mechanism still remains the same. The engine is still connected to the compressor with a belt.

This is a more simplified design. A low-energy-consuming solenoid controls the output of the compressor instead of controlling it with a high-energy-consuming electromagnetic clutch.

But when the AC compressor is turned off, the clutch is automatically disengaged from the pulley. So the pulley keeps wheeling freely around the compressor. As a result, it accounts for only a small amount of load from the engine, which helps the pulley to rotate on its own bearing.

How Can A Faulty Compressor Affect The Engine?

Here’s the deal. A faulty compressor might not cause any problems with the systemic engine if the fault is inside the compressor. If the accessory belt breaks down, gets damaged, or slips from its position while being used, the compressor will not be able to function properly.

The belt not only supplies the compressor but also helps in regulating other important functions of the car. The most important function of the accessory belt is to control the power steering. It also supplies the water pump, alternator, and fan for radiator cooling.

So if the compressor is faulty because of the clutch and the bearings on the belt, it’ll prevent you from driving.

Will A Bad Compressor Stop The Car From Moving?

We’ve already discussed the possibilities. An air conditioner compressor will not prevent your car from moving if the defect is inside the engine. A defective AC compressor has nothing to do with the car’s engine unless the belt or clutch is the reason. But in most cases, the main reason for a bad compressor is a damaged belt or frozen clutch.

But if given a long time, a bad compressor will cause great harm to your car’s engine. The serpentine belt breaks or comes off its pulley when the compressor seizes. The belt starts to malfunction, and the alternator stops turning. It eventually causes the battery to run down and the car to stop moving.

But it doesn’t stop the car immediately. When the compressor seizes up, it harms the electric clutch or damages the belt.

Can A Bad AC Compressor Cause Engine Overheating?

The compressor itself will not cause the temperature of the engine to rise. But any problem engaging the electromagnetic clutch and the accessory belt might cause engine overheating by putting extra load on the engine. When the compressor has a bad bearing or is overcharged, it puts extra strain on the engine. This leads to engine overheating.

The accessory belt is often connected with the radiator cooler. Any fault in the belt will lead to further problems with the radiator cooling. It’s one of the most significant reasons for engine overheating. 

Symptoms Of A Bad AC Compressor

An AC compressor is a crucial part of your car’s air conditioning system. It compresses the air and pushes the refrigerant inside the car. As AC compressors work relentlessly, they are more susceptible to damage and breakdowns.

There are many reasons why a compressor is more prone to damage. They suck in air from the outer environment and put a lot of pressure on the air. Many foreign particles may accumulate and cause malfunctioning. Besides, the bearings, belt, and clutch can get broken or torn over time.

At the onset of malfunctioning, a bad compressor will continuously show some signs to the passengers and the driver. The compressor is in charge of pressurizing and transporting the refrigerant, so any issue regarding the compressor will lead to further problems with the air conditioning system and the engine.

These are symptoms of a bad compressor:

1. The Cabin Temperature Increases

The most confirmatory and clear sign of a bad compressor is that the air conditioning will no longer blow as cold air as it used to do before. The warm air can easily be felt when the cabin temperature rises. A faulty AC compressor will not decide and adjust the flow and will fail to transfer the refrigerant into the air conditioning system.

2. The AC Compressor Will Make Loud Noises

When you turn the AC on and you hear loud sounds coming from your system, it can be a clear signal of a broken compressor. The accessory engine belt drives and controls many important parts of the systemic engine, including the ac compressor. It has a complex mechanism comprising many interior components. It has a sealed bearing on which it turns.

When any component of the internal part breaks down with time or the internal bearings of the ac compressor get frozen up, the engine will produce loud noises. The sound will be high-pitched, loud, howling in the case of a leaking or damaged bearing. A low grinding noise comes from a seized bearing.

Since the mechanism and the internal components are complex, it’s better to replace the compressor with the help of a professional instead of trying to fix the compressor in your garage.

3. Malfunctioning Of The Compressor Clutch

Sometimes the clutch fails to move in a defective compressor. The clutch connects the pulley of the compressor with the engine so that it can engage and disengage when the system needs it to. So the clutch is important for keeping the system activated. Consequently, a defective clutch can cause a bad compressor, which will affect the engine.

Diagnosing A Bad AC Compressor

You need to conduct a series of tests to diagnose the main cause of your car’s issues. Air conditioning is one of the most important parts of your car. A bad AC compressor can seize the car’s engine. And this will lead to loss of control over the steering and brake failure. So if you’re driving a car and suddenly the engine stops working because of a bad compressor, there’s nothing more awful than that.

Here are some ways that will help you to diagnose a bad ac compressor.

1. The Temperature Fluctuation

If you turn on the AC and it doesn’t blow cold air, there’s a high chance your compressor has some issues. Keep a close eye on the sudden fluctuation in temperature.

2. Check Your AC Compressor

Find your AC compressor and check whether there’s any damage, rust, oil leak, or loose connection. Lack of oil in the compressor can lead to compressor defects.

3. Check The Belts

The accessory belt is a vulnerable part of the compressor. If it gets broken or gets torn, it’ll affect your engine.

4. Check The Clutch

You can find the clutch in front of the compressor. There should be enough room for the clutch to roam freely. Turn the clutch’s hub and check whether it has become stiff. Ensure the resistance and frictions are minimal.

5. Check For Any Refrigerant Leak

The air conditioning system is a closed system, and it doesn’t leak generally. The best way to detect refrigerant leaks is to use a leak detector tool designed for refrigerants.

6. Turn On The AC At The Highest Setting

While driving the car, turn the AC on to the highest setting. After driving for a while, open the hood and check the clutch as well as the compressor. If you see the engine is overheating or the clutch isn’t engaging, then there’s a high possibility of a defective AC compressor.


The AC compressor of the engine is a busy unit. It is more prone and susceptible to damage than any other part of the system. The mechanism of the compressor is complex and consists of many parts.

Any damage to the compressor will stop your air conditioning system from working properly. But, will a bad ac compressor affect the engine? Mostly yes. If the belt or clutch is causing defects in the compressor, it’ll affect the engine.

So, if you get any sign of a bad ac compressor, go to the nearest mechanic and fix this problem.

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