Car Air Conditioner: How to Fix AC in Car? Repair Car AC

It is for all purposes inevitable that the air conditioning system of a car becomes less and less effective over time, until the day when you turn the knob and you are met with tepid, hot breezes as you roast in the summer heat.

It is kind of flexible, but generally, your conditioner needs to be recharged for a few hundred dollars, and the self-repair cans have pretty bad reputations over the years for doing a subtly dangerous job.

The dashboard of modern cars has warning lights that alert you to anything from tire pressure to engine problems. There are no specific warnings about air conditioning in most cars. When there is a problem with your car, you may notice a foul smell whenever the air conditioner is turned on, or the air blows warm instead of cool. You will usually see more than one problem causing the symptoms you are experiencing with your air conditioning system.

Define Car Air Conditioner

An automobile air-conditioner works on a similar principle as your space air-conditioner or a refrigerator. The elemental principle concerned is heat-exchange. A refrigerant gas forces the transformation of liquid to gas back to liquid, and within the process, it absorbs or releases heat. Heat is absorbed once it expands from liquid to gas form.

The mechanical device of an AC compresses the unaggressive gas into aggressive, heating it up in the process. The condenser and therefore the fan force this gas to chill down, turning it into a high-pressure liquid form, losing a number of the warmth in the process. This liquid aggressive refrigerant flows through the growth valve simply before it enters the cabin, permitting it to expand, reducing pressure, and cooling it down.

Also Read: Types of Cars

Various Parts of Car Air Conditioner


Compressors are pumps that distribute Freon to all parts of an automobile’s system. Freon is sucked in first by the compressor and then distributed to all parts with high pressure in the form of gas.

The compressor of your car’s air conditioning system is driven by the crankshaft of the engine.

It is possible to divide the compressors in an air conditioning system into two categories: reciprocating types and the rotary type. The Crank type and swash type are the primary examples of the reciprocating type, whereas the rotary type advances through the vane type.

Compressor Clutch

This pulley provides a connection between the engine speed and the compressor since it is directly connected to the crankshaft with a V-belt.

Once the air conditioner is turned on, the AC coil becomes electrified, causing it to become a magnet. The magnetic coil then attracts the clutch disc which locks the AC pulley. So that the compressor can operate, the pulley transmits its rotation to the compressor shaft.

Also read: Types of bikes


A condensation process occurs in the condenser which changes the form of the Freon which then passes through the compressor. The condenser functions to cool high-pressure Freon gas after it passes through the compressor.

Condenser pipes are made of curved and fitted with fins, so that heat can be dispersed as quickly as possible. Therefore, condenser pipes need to be cleaned to ensure that heat is not distributed during heat transfer.

Condenser Fan

During the heat absorption process, the condenser fan blows air over the condenser so that it can absorb heat. The fan also helps cool the condenser section.

Expansion Valve

Expansion valves convert Freon from liquid to gas & also controls the amount of Freon that flows through it. This component consists of a tiny channel that connects the filter dryer and the evaporator. Despite the fact that automobiles come in a variety of shapes and sizes, the primary components of car air conditioners are nearly the same. 

XPH is your home for BMW, Audi, Ford Mustang, VW, Porsche and Nissan GTR aftermarket parts.


If your car’s air conditioner doesn’t seem to be getting cold enough, the evaporator may be leaking. Despite the fact that automobiles come in a variety of shapes and sizes, the basic components of car air conditioners are nearly identical, but they must first be thoroughly evaluated. 

Filter Drier

Debris, dust, and water were transported by Freon, and are filtered by the filter drier which is an important component of your car’s air conditioning system.

Filter Drier can be found inside the receiver dryer. It also serves as a temporary storage facility for liquid Freon. Because water carried by Freon can freeze in the expansion pipe, it must be evacuated immediately. 

Also Read: What is Governer

Ventilation Blower

The Ventilation Blower is responsible for blowing Freon and air into the vehicle’s cabin. This ventilation fan is normally located under the dashboard of the car.

As a car owner, you should inspect this part because it is usually the first to become dirty. Clean the ventilation blower on a regular basis so that it can perform at its best while blowing Freon and wind as needed.

Pressure Switch

This is an important component because it functions as a safety mechanism for the car air conditioner. A liquid sensor is incorporated inside to actuate the pressure switch.

It can automatically control the air conditioner based on the Freon gas pressure, engine temperature, and other factors.

A connection cable connects to the compressor in addition to the pressure switch.  The purpose of the compressor is to adjust the freon gas pressure where the air conditioner is on. When a car air conditioners pressure is high, High-pressure service connection tool is needed.

Also Read: What is Engine

Key Problems in Car AC

Blocked Condenser

During your drive, the air that passes through the front of your car as you drive cools hot refrigerant.  You can imagine that it is a condenser re cooling hot refrigerant after it has been compressed.

Whether it is a piece of road debris or something else, if the condenser is blocked it cannot cool the refrigerant as it should. As a result, your vehicle’s air conditioning system will continue to expel hot air.

If you see anything blocking the condenser in your front grill, it can easily be removed and the problem should be fixed. The condenser can often be found near the front of your car, so it should be easy to look at if anything is blocking it.

Spring is here! Save big on our best-selling WAGNER TUNING BMW F CHASSIS N55 CATTED DOWNPIPE

No Air coming out of the Ventilator

This issue isn’t as clear-cut as hot air returning through the vents. A knowledgeable technician will have to be compelled to eliminate the doable causes by checking many parts first.

If the ventilation fuse blows there’ll be no power to the blower motor preventing air from processing through the vents. Likewise, a nasty relay also can be the offender since the relay takes the tiny electrical current and uses it to control the larger current required for ventilation.  

The blower motor is what pushes the air through the vents within the car, like a disciple in your home. Blower motors that have malfunctioned because of wear or age can stop air from returning through the vents. Similarly, the blower electrical device works with the blower motor to regulate the amount of what quantity of air is created to flow through the vents supported by your preference corresponding to low, medium, or high.

The car has two particular areas where air enters the system of the vehicle. One is where air enters your vehicle through vents by the lower half of the screen and also the alternative is that the air that’s re-circulated from within the cabin. If either of the air intake areas is blocked by a clogged filter or alternative debris, your vents could blow very little to no air. 

The air-conditioner system is supplied with several hoses and belts that operate the system. Any kind of leak, detachment or blockage can stop the correct flow from the vents.

Also Read: Fuel Pump

Lack of Consistency

Sometimes you’ll have a drag that comes and goes. This is the foremost frustrating as a result a mechanic can often tell you there is no problem with your car’s AC. The mechanic has to expertise the difficulty once they check the car. They have to recreate the issue so as to diagnose and fix it.

If your air-con system generally runs fine so sometimes won’t, there could be a couple of totally different causes. This might be one thing as straightforward as a blown fuse or a leak in one of all the seals. It would be something additional serious, like a problem together with your mechanical device or the mechanical device clutch. There might also be a clog somewhere within the system.

Leak in the Refrigerator

There are many possible places where refrigerants can leak in an air conditioning system, making it hard to pinpoint the exact location. The most common place is at the AC unit hose connection where the refrigerant can leak.

A leak likely originates from an oily substance that gathers around these connections. You can seal the leak with a sealant designed for air conditioners that can be found at most auto parts stores.


Electrical Issues

AC units that have stopped working may have electrical problems, which are perhaps the most difficult to diagnose. In order to determine if any wires are frayed or broken, it is first necessary to conduct a visual inspection of all the wiring.

You should repair damaged wires with electrical tape or replace them entirely if they are seriously damaged. In the event that you cannot see any electrical issues on your vehicle, it may be time to take it to an experienced dealer for further diagnosis.

Broken Cooling Fan

It is possible for your condenser not to receive proper cooling when fans are not functioning properly. Your car can start emitting only hot air as a result of this over time. Visual inspection is the best way to determine whether the cooling fan is defective.

Debris on the road can cause cracks in the fan and replacement is the only solution to this problem. Blowing fuses and other electrical issues are other common problems with cooling fans. If you do not have any experience with electrical work, you may need to hire a professional.

Also Read: Gear Box

Mildew Issue

If you turn on your air conditioner and notice the noxious smell of mildew, this is caused by bacteria growing inside the system. That is due to less use or frequent use of the AC in the car. As a result, the maximum setting is due to extra moisture in the unit. 

Some bacteria or other microorganisms develop behind the evaporator’s dashboard. It produces a bad smell that is coming out of the vents.

Broken Condenser

It’s possible that the condenser is completely broken if there is nothing blocking it. You may break a condenser when a piece of road debris punctures the grill of your car, causing the part to crack, or when your car’s equipment fails.

Visually inspecting your condenser for any punctures may reveal that it needs to be replaced if there are any.

Would you like to test?

Compressor Issue

Your air conditioners compressor keeps it running continuously. You won’t get any cold air if the refrigerant cannot circulate. 

Long periods without use are one of the most common reasons for a compressor to fail. After a long period of inactivity, the system is often shocked when it is finally used again in the spring or summer after sitting idle all winter.

This prolongs the life of the compressor & the best way to combat this issue is to run your conditioner for 15 minutes at full blast approximately once every three weeks, regardless of the weather.

Workflow of Air Conditioner

An air-con system begins with the compressor, which takes the liquid refrigerant. After that, it compresses into gas & towards the condenser by forcing it out.

  • The condenser works in an abundant constant approach because of the engine’s radiator. In fact, the condenser sits before the radiator underneath the hood and appears tons a sort of a second radiator. The refrigerant enters the condenser under air mass and extreme heat. Because it passes through the condenser, it offers up its heat to the air and flips into a liquid; much the way steam would turn into water is cooled.
  • The liquid refrigerant is shuffled off to the receiver-dryer, a reservoir that contains desiccants, kind of like the package of granules within a pillbox that absorbs the wetness within the container. As a result of any water in the AC that might freeze and stop the refrigerant from flowing, it should be far from the receiver-dryer. The desiccants additionally take away different impurities to stay the refrigerant clean and functioning.
  • From there, the cold liquid refrigerant flows to the evaporator wherever the work of cooling cabin air gets done. The evaporator is solely a part of the AC system that’s not set within the engine: it’s sometimes close to the feet of the front passenger. The coil of tubes permits the refrigerant to soak up the warmth of the cabin whereas an addict blows the cooled air through the vents. Because the refrigerant picks up heat, it turns into gas and heads once more to the mechanical device to start the cycle again.
  • The evaporator additionally removes humidness from the cabin, which helps the folks within feel cooler. This can be the water you may see dripping underneath the automotive on a hot day not like dripping refrigerant, a water leak isn’t a problem. Compressors, condensers, and evaporators will break down, as can any of the smaller components of the air-con system, however, a refrigerant leak must always be thought of initially because of the possible culprit.

whether or not it’s a leak or one thing else that’s inflicting your cooling system to wish to recharge, use the correct refrigerant sort supported by the make, model, and year of your car or truck to stay the system running smoothly.

Become a Six Sigma Green Belt Expert by mastering concepts like Fishbone/Ishikawa diagram, Root Cause analysis, Co-relation & Statistical analysis of data while working on industry based Use-cases and Projects.

Efficiency of Car Air Conditioner

Window Shading

When sunlight does not penetrate into your car’s interior; it won’t exert as much effort to keep the temperature cool. Modern car glass blocks UV and infrared light, but not visible light. As the light penetrates through the glass, it can cause the temperature to rise.

You can limit the amount of heat buildup in your home by installing window shades. Of course, buying window shades check your local laws to make sure the ones you’re planning to buy are legal in your area.

Cleaning the Condenser

Air condensers are usually found right behind the grill on the front of the car. They re-cool the refrigerant of the AC by releasing the excess heat into the air passing by.

Nevertheless, dirt and debrief can clog the airflow path, resulting in much-reduced cooling efficiency. Be sure that the device is regularly inspected and cleaned to ensure that its functions at its best.

AC Curtain Installation

When there are only a few occupants in larger SUVs, Minivan, and MUV’s, it will be inefficient to cool the entire interior. An AC curtain can reduce the area within that needs to be cooled, and allow the vehicle to reach a comfortable temperature more quickly.

Join thousands of businesses who thrive with LearnWorlds smart e-learning technology, award-winning support, and inspiring content.

Ac Filter Inspection

One of the causes behind the breakdown of your car’s air conditioning system is worn-out, dry air filters. Over time, these filters can become clogged, which can lead to the failure of the system.

Recirculation mode of Air conditioner

You might be better off switching your air conditioner to recirculation mode than letting it cool air from outside, especially if the outside temperature is above 100 F. Before you start driving, roll down your windows for a few minutes, and set the air conditioner for fresh air.

Open the sunroof as well- hot air will rise and will escape the car much faster than this way. Afterward, close the windows and turn the AC on recirculation.

Refrigerator Inspection Properly

If you frequently use a car’s air conditioner, this can cause a gradual loss of refrigerant through leaks. A refrigerant shortage in the system can result in poorer performance, especially during high temperatures. 

Do start AC while moving

It is common for many people to start the air conditioner before driving. However, this can waste both time and fuel. Your car’s air conditioner will perform better while driving as the engine’s crankshaft enables the compressor to run faster.

Types of Refrigerator Car Air Conditioner

R134a Refrigerator

The refrigerant possibly in your vehicle these days is R134a, the Freon replacement chosen for its effectiveness and low risk of flammability. R134a is kinder to the gas layer; however, it is no longer environmentally friendly. R134a contains greenhouse gas emissions that do not break down quickly.  As a result, it contributes to the global warming that characterizes climate change.

R12 Refrigerator

Until 1995, the universal refrigerant for automobile air conditioners was Freon, the aerosolized component typically called R12 refrigerant. Freon worked well as a result of its cheap and cools to a liquid at around the melting point of water however otherwise remains in an exceedingly gaseous state that absorbs heat well.

Unfortunately, heavy use of dressed Freon contributes to the rapid depletion of the earth’s gas layer, which filters out most of the sun’s harmful ultraviolet rays. This can be why Freon was illegal from all new cars sold-out within the U.S. beginning in 1995. It’s still legal to drive associated automobiles with Freon refrigerant within the AC system as long as the vehicle was factory-made before 1995. Several classic automobile homeowners have retrofitted their vehicles to use a Freon replacement for their AC units.

R1234yf Refrigerator

Vehicle makers began the transition to victimization R1234yf in AC systems many years past in anticipation of the federal mandate to modify from R134a last year. Twenty-seven of the highest forty merchandising automobile and truck models had outfitted their air-con units to run on R1234yf by the end of 2019.

This new refrigerant works also like its predecessors whereas breaking down into harmless parts in eleven minutes, inflicting virtually no environmental impact. It’s been needed in vehicles sold-out in Europe since 2011 and is turning into the norm within the U.S. as well. The one disadvantage of R1234yf is that it’s flammable; however, explosive into flames has not been a difficult when a decade of use in Europe.

Problems and Solutions on How to Fix Car AC: Repair

Define Black Death

An automobile air-con system experiencing bubonic plague is going to be infected just like the plague. The Black Death begins inside the mechanical device when the coolant fails.

Since refrigerant acts as an operating fluid very similar to however gasoline is the fluid that has lubrication to guard the engine, a refrigerant breakdown can end in ugly wear, beginning within the compressor.

From there, the sharp and soiled metal particles created throughout compressor breakdown will then travel through the remainder of your ac system, wreaking disturbance on the complete system. All Cold Air & flow will be long gone before you know it.

Can you fix your car’s ac on your own?

There are some things that a novice will fix themselves, although it’s not suggested that you just attempt to repair the automobile ac while not information on car repair. If you don’t have any plan for what the problem is, it’s best to induce a competent mechanic to diagnose and repair the issue.

That being said, there are some problems that you can ably repair and maintain yourself. For example, recharging your car’ ac is often accomplished simply and with stripped-down cost. You ought to still confirm that the remainder of the system is running optimally, though. Typically your car just desires a recharge, however, typically it’s losing refrigerant as a result of their’ a leak that ought to be repaired. If you’re exceptionally handy, you would possibly even be ready to check and alter a blown fuse or change the filter for the cabin.

What is the key reason behind a leak in car AC?

Age and wetness are the plain and easy reasons for the leak. Rubber seals and hoses can lose their click over time and break, allowing Freon to escape and moisture to enter the vehicle’s fuel system.

Wetness is the death kiss for your air conditioning system, which is mixing with refrigerant and creating a system that destroys corrosive acid. Moisture can damage the battery, receiver, or dryer in your air conditioning system. These devices are responsible for removing moisture from the AC system. Furthermore, it can eventually fail when exposed to an open system leak or crack.

Why your car AC is not blowing strong cold air?

Sometimes your air is processing out and it’s cool, however, it is merely not blowing out as sturdy because it did. You would possibly crank up the ac to the best setting and still solely feel as if you’ve got it on low or medium. This could be caused by many issues. It’s going to be one thing as straightforward as a loose hose or seal that has to be replaced. It would be something a touch a lot invasive, sort of a faulty fan. this could even be caused by a buildup of mildew within the system.

Tips and Tricks to Fix AC in Car: Repair

Clean the Air Filter Regularly

The air filters in your car keep the engine clean. A dirty filter causes the airway to clog and the AC to fail to cool.

Read the manual of Car Owner

The owner’s manual of your car is like a holy book. The maintenance list for your car should cover all the parts that are likely to last a long time. Your AC needs to be maintained properly by replacing these as soon as they show signs of wear.

Check Up your Car AC Every Year

Although this is one of the easiest solutions, people have failed or forgot to implement it.

Because people thinks do not fix until it isn’t broke, don’t make it worse. It’s a good idea to have your car’s AC system checked or diagnosed every year even if it’s working properly. Evaporator, condenser, and compressor are the only components of your AC system that operate. A regular check-up is vital for these components as well, especially when your car is 5 to 10 years old and is prone to wear and tear.

Remove Bad Odor

Cars have defroster strips or defoggers, which generate heat when they are turned on to eliminate fog and moisture. After operating your air conditioner for a long time, you should dry out the evaporator. Doing so prevents mildew and odors in the system.

Start Defrost Mode

It prevents mildew and eliminates excess moisture, which can cause your car to smell unsavory.

Recharge AC System

Refresh the cooling system after two years with gas and lubricant. The higher the fan speed and the cooler the setting, the better the gas pressure will keep the compressor running properly.

Remove Excessive Humidity

Another purpose of an Air conditioner is to remove humidity in addition to cooling the vehicle. That is extremely useful when you need to remove fog from the windshield to improve visibility.


What is the reason behind car AC stop working?

It is possible for an electrical issue to affect your car’s air conditioner. It could be a blown fuse, a failed switch, or a problem with the control module. It is easy to fix an electrical short caused by shorted fuse, or a loose connection that stops AC from properly functioning.

Why is Your AC not providing coolness?

Your central AC might not be blowing cold air because of a leaky refrigerator, which is running low. New refrigerant must be added to the system to provide coolness to your car air conditioning system.  A leak not only prevents the AC system from cooling properly but has the potential to cause other problems inside the car as well.

Having a Car AC means cooling in Car?

There may be a centralized panel, but AC is primarily for cold air and reduced humidity. The only heat she will get there is from her engine as the heat exchangers warm up.

High Rated Automotive Engineering Course

Automotive 101: A Beginners Guide To Automotive Repair

Automotive Engineering: Automobile Fundamentals and Advanced

Automotive Engineering; Hybrid Electric Vehicles

Do it Yourself – Automotive Electrical Diagnosis – Beginner

Do it Yourself-Automotive Electrical Diagnosis-Intermediate

Automotive Engineering; Common Rail Direct Injection(CRDI)

Fundamentals of Internal Combustion Engines – IC Engines

Hybrid and Electric Vehicle for Beginners FULL Course 2021

Automobile Safety: Understanding Car Crashes for beginners

Hybrid Vehicles The Fundamentals & Operating Principles

Introduction to Automotive engineering – Performance

Automotive 102: Battery, Charging System & Starting System

If you are interested to have certificate programs

Get started in your dream career today with 60% off registration at IAP Career College.

Our Videos

Refer YouTube

Our Apps

Check out our ‘MechStudies – The Learning App’ in iOS & Android

Check out our most viewed articles,

What is thermodynamics

Intensitve & Extensive Properties

What is Pressure

Bernoulli’s theorem

Venturi meter

Pump basics

Globe valve


Reference Articles


Hello Everyone! We are the MechStudies team and really delighted to present our articles. We will capture all types of Mechanical Engineering articles in the simplest way with various diagrams, practical examples, etc. Cheers!

Leave a Reply

Your email address will not be published.

Recent Posts

You cannot copy content of this page