Will a Bad AC Compressor Affect the Engine Performance?

Will a bad AC compressor affect the engine?” is one of the most asked questions we’ve ever received. This question has become important in recent times, given the climate change that has swept across the world.

Will AC Compressor Affect Engine_s Performance

Many people are keen to find out if they can drive with the AC off in extremely hot weather without worrying about engine performance. Well, we have the answers for you and give an in-depth explanation of what we think about the subject.

Can a Bad AC Compressor Affect the Engine?

Yes, a bad AC compressor can affect the engine’s performance and longevity. The AC compressor puts the refrigerant under pressure and circulates it in the AC system. Though you can drive the vehicle, we’ll advise you to get help as quickly as possible before the engine starts developing problems.

What Are the Effects of a Bad AC Compressor on an Engine?

The effects of a bad AC compressor on an engine is overheating, engine strain, low fuel efficiency and issues with the serpentine belt. Other issues that could crop up include reduced fuel efficiency, fluctuations in engine power, driver discomfort and the car’s resale value.

Engine Overheating

A bad AC compressor influences the engine’s performance in a few ways. First, a faulty AC compressor puts extra load on the engine, forcing it to overwork and eventually become too hot. It occurs when the compressor’s clutch is engaged, but the compressor doesn’t function properly. This forces the engine to make up for the compressor’s failure, exerting extra pressure on the engine, resulting in overheating.

Overheated Engine With Steam

A failing AC compressor can cause fluctuations in the car’s electrical system, which might affect the cooling fans. The cooling fans help the car’s temperature management system to keep the engine working at optimal temperature. Thus, when the cooling fans fail, they won’t produce enough air to cool the engine, leading to overheating.

Also, the bad AC compressor might cause the condenser to fail because the two work in tandem. The condenser’s work is to dissipate the heat from the refrigerant after it has been heated by the compressor. An AC compressor failure leaves debris that ends up in the condenser, causing it to fail. This is why mechanics advise drivers to change condensers and compressors at the same time.

Strain on Engine

As we’ve already discovered, a bad AC compressor puts a strain on the engine, and this is possible because of the link between the two components. The engine crankshaft pulley is linked to the AC compressor via the serpentine belt. When the pulley spins, it turns the belt, which, in turn, drives the AC compressor. Now, when the car AC compressor fails, it creates resistance within the belt, which the engine pulley tries to overcome.

Mechanic Working On A Strained Engine

The struggle to overcome the resistance puts a strain on the engine, causing it to overwork. Also, a failing AC compressor will try to make up for its failure to compress the refrigerant by putting pressure on the engine. This pressure, combined with the strain on the engine, can cause overheating in the vehicle.

Low Fuel Efficiency

A damaged AC compressor contributes to reduced fuel efficiency as the engine strains to make up for the power loss. As the compressor increases the load on the belt, the engine demands more power to overcome the resistance. Since the engine runs on gas, it burns more fuel than it is used to help power the extra demands. This causes reduced fuel efficiency, which puts a strain on finances.

Driver Discomfort

When the AC compressor is faulty, it fails to produce enough air to cool the car interior, making it uncomfortable for the driver and passengers. Given the soaring heat in some parts of the country, this can be very discomforting.

Driver Feeling Uncomfortable Because Of Heat

Aside from the heat that comes from outside, the heat produced by the engine can find its way into the interior, depending on the direction of the wind. This will compound the high cabin temperatures, making the occupants of the vehicle uncomfortable.

Affects the Car’s Resale Value

If you intend on selling your vehicle with a damaged compressor, then you may be forced to sell it at a cheaper price than the market value. Many buyers prefer vehicles with a good AC system due to the comfort it brings; thus, they’ll avoid vehicles with non-functional ACs. The few patrons who want to purchase the vehicle will negotiate for a lower price. Their reason is that they’d use the difference in prices to repair the bad AC compressor.

Electrical Load on the Engine

Most AC compressors feature electromagnetic clutches that switch it on and off at regular intervals. This action helps to heat the refrigerant, circulate it throughout the system, and switch it off so it can cool down.

A Look On Engine_s Battery

However, a faulty compressor might cause the clutches to stay on, failing to go off so the condenser can cool it down. When the clutches stay on for long, they draw more electrical power than usual and put pressure on the engine.

What Are the Signs of a Bad AC Compressor?

The signs of a bad AC compressor are warm air, noises from the AC system, a bad smell, fluid leakage, engine problems and vibrations in the steering wheel. Other faulty AC compressor symptoms include stuck clutches, electrical issues and increased strain on the engine.

Warm Air in the Car

The major sign of a failed compressor is hot air circulating in the car even when the air conditioning is turned on. The AC compressor plays a major role in keeping the car cool by circulating the refrigerant in the AC system. Thus, if the refrigerant doesn’t travel through the system, it won’t produce much-needed cold air. Rather, it will lead to an increase in warm air as the engine strains to meet the demands of the air conditioning system.

Woman Struggling Because Of Warm Air In Car

This situation can be uncomfortable, especially during the hot summer afternoons. Note that a malfunctioning AC has several causes, with a malfunctioning compressor only one of them. Thus, don’t conclude that the compressor is faulty just because the AC isn’t working correctly. You have to inspect the compressor to be sure it’s the culprit here.

A Bad Smell Coming From the AC

Another sign your compressor may have problems is a bad smell emanating from the AC. One reason for the smell is fluid leakage in the AC system. Fluid leakage in the AC system could be a perfect breeding ground for microbes. When these microbes multiply, they produce an odor similar to that of mildew, which is circulated in the car.

Also, leaving the AC compressor for too long without repairing it could cause mold to grow. The reason is that the AC system is always moist, thus encouraging the growth of mold. When it multiplies, you’ll begin to perceive a raunchy smell in your vehicle.

Loud Noises from the AC Compartment

Hearing loud sounds after the AC is turned on is an indication of compressor issues. The noises are usually screechy or squeaky and can be unsettling. The compressor has several components like bearings, pulleys and coils. Any of these components could become loose or faulty and generate squeaky sounds whenever you turn the AC on.

Car Air Conditioner Can Make Too Much Noise

When the AC compressor starts producing unsettling noises, know that it is about to give up; thus, don’t delay in repairing. Thus, get a qualified technician to do the replacement to avoid compounding the issues.

Excessive Vibrations in the Steering Wheel

When you experience vibrations in the steering wheel when the AC is turned on, the culprit could be the compressor. Of course, there are lots of reasons why the steering wheel will vibrate, but don’t rule out the possibility of a failing compressor. The vibrations could be the result of the engine straining to power the AC system. It could also be caused by a loose component in the AC compressor unit, which needs to be tightened or replaced.

A Bad Compressor Clutch Leading to Loss of Pressure

An AC compressor clutch helps circulate the AC throughout the engine by engaging and disengaging the compressor. If the clutch is faulty, it won’t engage the compressor properly, causing it to malfunction. A failed clutch will lead to loss of pressure in the AC system and result in engine overheating.

How To Address AC Compressor Issues Affecting the Engine

Addressing AC compressor issues affecting the engine involves running a series of tests to ascertain where the fault is from. Also, you need to physically inspect the compressor and the clutch for loose components and other problems. You also need to inspect the entire AC system for refrigerant leaks.

We recommend that you check the temperature fluctuations to determine whether the compressor is failing. For example, if the air coming into your vehicle is still warm, the chances are that your compressor is about to give out. Also, remember to inspect the belts to ensure there’s enough tension. Also, look for abrasions, cracks and holes along the belts because they could be the reason why the compressor is down.

Once you’ve determined the source of the problem, it’s time to repair them. Many professionals advise that you replace the entire AC compressor instead of repairing only faulty parts. However, we suggest that you replace some parts, like the belts, when they’ve lost tension or have developed cracks. Also, components like ball bearings and loose pulleys can be replaced instead of changing the entire AC compressor.

Frequently Asked Questions

Can a Bad AC Compressor Cause Rough Idle?

Yes, a bad AC compressor can cause rough idling by putting extra load on the engine. This extra load causes the engine to strain and result in rough idle. Also, a bad compressor can cause a clutch to malfunction, which affects the load distribution in the engine.

Uneven load distribution then leads to rough idling.

How Long Can You Drive With a Bad AC Compressor?

You shouldn’t drive any amount of time with a bad AC compressor, as it can lead to engine overheating and several engine issues. Whenever you detect a faulty compressor, repair it immediately to avoid aggravating the situation. It is best to replace the entire compressor unit, as this ensures longevity.


We’ve discussed the dangers of a bad AC compressor, the symptoms, and how to address the issues that crop up.

Here’s a recap of all that we’ve discussed so far:

  • It is not advisable to drive with a faulty compressor, as it can put a strain on the engine, cause overheating, reduce fuel economy and affect the car’s resale value.
  • A malfunctioning compressor can also strain the electrical load of the vehicle and cause discomfort to the driver and passengers.
  • Some of the symptoms of a damaged compressor include a raunchy smell, warm air from the AC, squeaky noises, and excessive vibrations in the steering wheel.
  • To determine the reason why the compressor is malfunctioning, you’ll have to run a series of tests, physically inspect the compressor and check the temperature fluctuations.
  • Many professionals advise that you replace the entire system to ensure it works well instead of trying to fix it.

However, if the fault is the serpentine belt or a pulley, replacing them won’t pose much of a problem in the future. A bad AC compressor replacement cost will be around $1,500 and $1,800, considering labor costs and all.

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