Can A Bad AC Compressor Cause A Car To Stall?

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A fully functioning AC compressor in your car can contribute to the car's overall performance. However, you might wonder if it becomes bad, would it stall your car? Wonder no more! As we're curious too about your concern, so we researched about it. Uncover our findings below!

A bad car AC compressor can cause your car to stop or stall suddenly. You must ensure that your vehicle and AC system are always following their regular maintenance schedules to avoid encountering this issue.

Stay with us if you continue to wonder why your car keeps stalling or if it will harm the engine. These are among the answers waiting for you to uncover below. 

How Does A Car AC Compressor Operate?

The compressor is the engine that drives the air conditioner. It applies intense pressure to the refrigerant before pumping it into the condenser, where it transforms from a gas to a liquid.

The compressor must be in perfect working order for the AC to run at its best performance. In addition, the AC compressor employs a belt that connects your car's engine to the AC compressor. The belt must be in good condition to ensure it will not slip while the compressor cycles.

Why Does My Car Stall When I Switch On My AC?

Why Does My Car Stall When I Switch On My AC?

Experiencing your car stalling can be frustrating, especially if you can't get help right away. So figuring out why this problem occurs is the first step toward fixing it. Here are the three major causes of why your car stalls:

Bad AC Compressor

A bad AC compressor is to blame if your car stalls while starting your car's air conditioner. This will result in demand for more horsepower in your car's engine compared to its normal status.

A Defective Idle Air Control (IAC)

The IAC is a valve you'll find in the throttle body which helps the car's engine to work properly. In essence, a car's engine requires a constant and sufficient air supply to run as it should. The throttle is responsible for the air to move; by operating the gas pedal, it controls the air precisely.

However, while the engine idles, the throttle is closed or shut off. This means that the car's engine needs another source of air supply without opening the throttle. So now the IAC will come into play. It ignores the throttle's function to keep running the car's engine; it also injects air into the engine without pressing the gas pedal.

The IAC's ability to function properly can have a big impact on how well the engine idles. Turning on your car's air conditioning system causes some pressure and stresses your car's engine. Therefore, a defective IAC will result in stalling your car when you try to turn on the AC. Schedule your car service to replace it and avoid this issue.

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Weak Battery And Faulty Alternator

Another reason why the car stalls is a faulty battery or alternator. As you know, your car's engine draws power from your battery and the alternator charges the battery to ensure it provides energy.

Switching on your AC signals your car's battery and alternator to supply power. If either isn't working at capacity, there won't be sufficient power, and the car might stall in an effort to operate the AC. Call your mechanic to replace both of them if necessary.

Can I Drive My Car If Its AC Compressor Is Bad?

Air conditioning compressor in a passenger car seen from below

The AC compressor is essential to efficient AC function but does not influence the vehicle's performance. You can drive your car with a faulty AC compressor as long as you do not use the air conditioning while you're in motion.

Will A Bad AC Compressor Affect My Car's Engine?

As long as the AC is turned off while driving, a damaged AC compressor cannot harm the car's engine.

The engine could certainly suffer if a bad AC compressor were running, as it would continue to demand horsepower from the engine. This is due to the compressor's pulley bearing failing, which eventually stalls the car as a result of the stuck compressor. Additionally, the belt could break, affecting every other component that associates with its system.

How Much Horsepower Do You Need For A Car AC?

You probably don't give much thought to anything as long as your car's cabin is cool. Remember that, the total power necessary to run your AC will also depend on how pleasant the outside temperature is.

Severely hot weather can strain the other vital components of your AC. Thus it makes car fuel consumption even higher.

Furthermore, this exactly contributes to the amount of horsepower that your car's engine is drawing to run the air conditioner. Presently, vehicles will need about four horsepower or three kW of overall engine power to start the AC.

What Are The Signs Of A Car AC Compressor Going Bad?

Proper evaluation of your car's air conditioning system is the most practical way to avoid early system breakdown. You'll want to service the AC system every three to five years.

The following are the signs of a car's AC compressor becoming bad:

A Strange Sound Near The Engine

Strange noises such as squealing, chirping, and whining coming close to your engine are due to two faulty parts. This includes the clutch becoming bad and a seizing shaft.

This issue results from compressor oil either lacking or not using the right type.

There's A Visible Rust Buildup In AC Compressors Body

Damage to the compressor's clutch or other external components could be a sign of internal issues. This is clearly due to corrosion which is also the caused by natural elements like moisture from your car's AC compressor.

An oil leak will result in a compressor failure. Therefore, any damage, including bending, breaking, corroding, or leaking, should be handled properly to ensure optimal AC operation.

The Compressor Clutch's Pulley Is Not Working

Technician use filler gates check compressor clutch on car engine

The good compressor clutch's pulley should engage instantly when you turn on the air conditioning. Otherwise, it won't spin and pump freon the way it should.

These are the common causes for the compressor not engaging:

  • Incorrectly grounded.
  • A low pressure lockout.
  • Damaged coil or faulty coil wiring.
  • Bad fuse.

Comply with the regular servicing maintenance of your car's air conditioning system. Doing so will guarantee you that your car's AC system will work at its best and serve you for more years.

How To Check A Seized Compressor?

A seized compressor is one of the main reasons why a car stalls when the air conditioning is on. The compressor has likely locked up if:

  • The car stalls.
  • A screeching noise is recognizable.
  • Or hot air blows from the vents.
  • A smoke coming out of the compressor.

BEWARE! when performing a checkup, you should at least allow the AC compressor to cool down to avoid unnecessary injury. 

Once you can finally touch the compressor, you'll want to inspect the clutch plate thoroughly. Any discoloration on the clutch plate could indicate the system is (or was) overheating.

Additionally, the clutch plate should turn relatively easily if the system is disengaged; try spinning it. You might need to use a socket wrench to stabilize the clutch plate nut while spinning it. 

Upon following our above steps and yet the issue persists. We highly suggest replacing your entire AC compressor unit. What's more, ensure to drain and save your compressor freon before completely replacing it.  

How Much Will It Cost To Replace A Car AC Compressor?

Auto mechanic repair automotive air conditioning compressor

You've had enough of dealing with and enduring all the same issues of having a bad AC compressor. Deciding to have it replaced is the least practical solution to fix the problem.

You should include in your budget the labor and parts expenses. The charge of labor alone is between $160-$200; meanwhile, the cost for parts is around $650 and $840. Your all in all average expenses will be around $1,100.

Of course, the only exception for this substantial cost will always depend on your local servicing center.

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In Closing

High angle view of new and used AC compressors

There's no denying that a bad AC compressor will stall your car. If you insist on using the air conditioning given that it is broken. Once you've noticed that indeed defective or misbehaving, go to your nearest service center right away. You can also consult your mechanic to have expert advice.

Need additional information about a car AC compressor? Kindly read our post below!

Can A Car AC Compressor Leak Freon?

Can You Replace Just The Clutch On An AC Compressor? Should You?

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