Most modern cars come with an electromagnetic AC clutch that, when engaged, transmits the belt’s power to drive the AC compressor. When disengaged, it only rotates the pulley with negligible resistance.
Yes, you can drive a car with a bad AC compressor with the AC turned off if the AC clutch and pulley bearing (pulley side) are in functional condition. Both the AC clutch and pulley bearing hardly ever go wrong.
- What Is an AC Compressor?
- Symptoms Of a Bad AC Compressor
- Will A Bad AC Compressor Affect the Engine?
- Can My Car Run Without an AC Compressor?
- Why Does an AC Compressor Go Bad?
- How Much Does It Cost to Replace An AC Compressor In A Car?
The serpentine belt that drives the AC compressor also drives several other accessories, such as the alternator, water pump, power steering pump, etc. Hence removing the whole AC unit is not a feasible option when the AC compressor has gone wrong.
What Is an AC Compressor?
An AC compressor is used to compress the refrigerant gas it receives from the evaporator to high pressure of 150-250 psi.
The high discharge pressure is required from a compressor in an air conditioning unit to work correctly and cool the air through the evaporator.
This hot compressed gas is then forwarded to the condenser, where it cools down through ambient air and condenses to a high-pressure liquid refrigerant.
This high-pressure liquid refrigerant is then expanded to a lower pressure gas in a capillary tube. It evaporates to produce the cooling effect, like the one when you evaporate spirit on your palm. Now, this cooled low-pressure gas is run through the evaporator.
Fresh or recirculated Cabin air is cooled by blowing it across the evaporator. This cold air enters the cabin again through the AC vent.
The refrigerant air-conditioning cycle goes on and on, where it is continuously compressed and expanded.
Symptoms Of a Bad AC Compressor
The most obvious symptom of a bad AC compressor is the lack of cold air through the air con. Some other significant signs that indicate a bad AC compressor are
Loud Noise During Operation
If your vehicle is making strange noises from the engine bay when you turn on the air-conditioner. Then it can probably be a loose AC belt or a problematic AC compressor.
A loose belt can spin over the AC pulley as it requires significant torque for working.
A loose serpentine belt can easily be tightened down by adjusting the tensioners. AC compressor, if damaged, makes odd noises due to failed bearings and loose or broken components.
Car Feels Extremely Sluggish with AC ON
If your AC compressor has gone bad, it will become harder for the engine to rotate it than before due to failing components. The AC compressor will increase the load on the engine, and it will result in a significantly sluggish behavior of the vehicle whenever AC is turned ON.
Will A Bad AC Compressor Affect the Engine?
A bad AC compressor will increase the load on the engine if engaged for cooling, considering it has not completely seized.
If a completed seized AC compressor is engaged instead, either the engine will stall, or the serpentine belt will slip and eventually break. It cuts off the power supply to the rest of the essential components such as the alternator, water pump, etc.
If a problematic AC compressor is never turned ON from the cabin, the chances are that it will never bother or put any load on the engine, assuming the AC clutch and the AC pulley bearing are functional.
Can My Car Run Without an AC Compressor?
You can permanently delete the AC compressor in a vehicle and run it without an AC compressor by replacing it with an air conditioning bypass or deleting the pulley.
These pulleys replace the whole AC compressor assembly along with the clutch and the old pulley.
AC bypass or delete pulleys are just pulleys that ensure tension remains in the serpentine belt and put no load on the vehicle’s engine.
If you do not want to spend money on replacing a seized or problematic AC compressor, and do not care about an air-conditioned cabin, then an AC bypass or delete pulley will do the job at a much lower price.
Why Does an AC Compressor Go Bad?
AC compressors can go bad over time for several reasons. We have listed some of the most common causes of car AC compressor failures below.
Ineffective Cooling on The Condenser Side
Ineffective cooling of the compressor discharge refrigerant due to dirt build-up on the condenser increases the temperature and pressure on the compressor outlet.
The compressor has to work harder to push the refrigerant to a higher pressure under even hotter conditions.
This significantly raises the level of wear and tear of the moving parts inside the compressor.
A refrigerant leak can decrease the amount of refrigerant in the AC lines. Hence, the compressor has to work for a longer time to cool down the same cabin to maintain the same flow rate.
Over-Filled or Wrong Refrigerant
If the refrigerant is filled past its prescribed pressure limit, it can cause an additional load on the compressor, resulting in premature wear and failure.
Line blockage anywhere in the AC cycle will increase the load on the compressor to push the refrigerant through the blockage.
How Much Does It Cost to Replace An AC Compressor In A Car?
Replacing an AC compressor with a new unit can cost between 600 to 1200 USD depending on the vehicle, vendor, and compressor specifications.
Replacement will be accompanied by refilling the refrigerant, which can cost 25 to 125 USD depending on the volume required, and the type.
The cost of mechanic labor for the whole process can range from 150 to 400 USD depending on the complexity of the job and placement of the AC compressor in the engine bay. It can take around 1-2 hours, depending on how easily accessible the AC compressor is.
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My name is Jeffrey Williams and I have been a car mechanic for over 35 years. I am currently working NYC Auto Repair Shop, in New York City and recently developed a strong passion about blogging. I decided to put together this blog where I will try and answer the most commonly asked questions I get on a daily basis from my customers.