Content

• To step
• Method 1 of 2: Part 1: Understanding the automotive air conditioner better
• Method 2 of 2: Part 2: Fix the air conditioner
• Tips
• Warnings

Have you been sweating in your car for a while because the air conditioning is broken? Here's a quick guide to how AC works, why it might stop working, and what you can do about it.

To step

Method 1 of 2: Part 1: Understanding the automotive air conditioner better

1. Realize that air conditioning in a car is really just a refrigerator in a different setup. It is designed to move heat from one place (the inside of the car) to another place (outside). A complete discussion of each specific model and component is beyond the scope of this article, but this article can help you figure out what the problem might be. Maybe you can fix it yourself afterwards or else you can at least intelligently talk to someone who fixes the air conditioner for you.
2. Learn about the main parts of the air conditioner in a car:
   • The compressor: it moves the (low pressure) gaseous refrigerant to the condenser (high pressure)
   • The coolant: this fluid transfers the heat. In newer cars, this is usually a substance called R-134a or HFO-1234yf.
   • The condenser: the heated coolant is pumped through the condenser. Here it gives off its heat to the driving wind or by means of a fan.Due to the drop in temperature, the agent becomes liquid.
   • The expansion valve: The liquid coolant in the car from the air conditioner is still under high pressure and flows to the expansion valve. It reduces the pressure by allowing a small amount of coolant through, it measures the flow and atomizes the coolant.
   • The evaporator: the coolant becomes gaseous again in the evaporator. The reduction in pressure causes the cooking to start and extracts heat from the air in the interior. The blower blows the air past the evaporator.
   • The filter drier: it removes dirt and moisture from the coolant.
3. Understand the process of air conditioning. The compressor pressurizes the coolant and sends it to the coils / fins of the condenser, which are usually in front of the radiator.
   • Compressing a gas creates heat. In the condenser, this heat and the heat that the refrigerant has picked up in the evaporator is transferred to the outside air. When the coolant is cooled to saturation temperature, the gas will be converted into a liquid (condensation). The fluid then passes the expansion valve towards the evaporator, these are the coils inside the car, where it loses the pressure that was added in the compressor. This ensures that part of the liquid is converted to a gas (low pressure) and that cools the remaining liquid. This mix enters the evaporator, the liquid part now absorbs the heat from the air and evaporates.
   • The car's blower circulates air past the cold evaporator and back into the car. The coolant will now go back into the cycle and everything will start all over again.

Method 2 of 2: Part 2: Fix the air conditioner

1. Check if you can see that there is a coolant leaking (then there is not enough liquid to dissipate the heat). Leaks are easy to find, but not easy to fix without taking parts apart. You can buy a fluorescent paint at the car supplies store that you can add to the cooling system to make it easier to find a leak. The instructions are on the bottle. If the leak is very large, it may be that there is no pressure on the system at all. Try to find the valve on the low side and check the pressure with a PSI pressure gauge.
   • Do not poke anything else in the valve to see if anything comes out.
2. Make sure the compressor is running.
   • Start the car, turn on the air conditioning and look under the hood. The compressor looks a bit like a pump and large rubber hoses go to it. It does not have a filler cap, but it usually has one or two valve-like protrusions on it. The pulley on the front of the compressor consists of a pulley on the outside and a hub on the inside, in the middle, which rotates when an electronic clutch is engaged.
   • If the A / C is on and the blower is on, but the center of the pulley is not turning, there is something wrong with the compressor clutch. It could be a fuse, a problem in the wiring, an AC button in the dashboard that is not working or there is too little coolant (most systems will automatically turn off the compressor if the pressure drops too low for protection).
3. Look for other causes of the problem. Other causes of a non-working air conditioner can be: a broken V-belt (preventing the pump from running), broken fuse, broken wire, bad switches or a broken compressor gasket.
4. Feel in the car if the air conditioning is working at all. If you feel cool air, but not very much, the problem may be too low a pressure. Then topping up the coolant could solve the problem. Read the instructions on the purchased coolant.
   • Never put too much coolant in it. More coolant than the recommended amount makes the air conditioning less effective. Better garages have a device that allows them to see if the cooling performance continues to improve while refilling. The moment it decreases again, liquid is removed again, until the ideal level is found.

Tips

• If you think the problem is bad wiring, most compressors have a wire going to the electronic clutch. Find the connection in the center of the wire and disconnect the compressor. Take a piece of wire, connect the wire from the compressor to the positive terminal of the battery. If you hear a loud CLICK, there is nothing wrong with the clutch and you should look for the problem in the car's wiring or a fuse. If you don't hear anything, the clutch is broken and the compressor must be replaced. Ideally, if you do this test with the engine running, you can see if the hub is turning in the center of the pulley. This way you can test whether the clutch works, but the pulley slips so much that no pressure is built up. Be careful not to get your fingers and any rags in between.
• The problem could also be the heat from the engine, which reduces the efficiency of the air conditioner. In that case you can try to insulate the cold airco pipe better.
• There is a light oil in the system.
• If there is a leak in your system while the drain pipe is clean, it may be that rainwater has entered the air conditioning system.
• Older cars and old-timers use the refrigerant R12. It is possible to have this system converted to R-134a.
• According to EU agreements, the introduction of HFO-1234yf should have taken place on January 1, 2013. Before that, car air conditioners were filled with R-134a refrigerant as standard. However, this is an extremely strong greenhouse gas with a "global warming potential" (GWP) of 1,430 times that of CO2. Given the strong tendency of car air conditioners to leak, Brussels therefore decided years ago that the use of this gas should end.
• The automotive industry is questioning the use of HFO-1234y as a refrigerant, according to a study by Daimler in September 2012, the substance is flammable. Volkswagen says it has now found a solution and will equip its passenger cars with air conditioning units with CO2 as a refrigerant.

Warnings

• Watch out for moving parts under the hood!
• Always be careful when trying to fix the air conditioner yourself. An expert at the garage has much more knowledge in this area, so always go to a garage if in doubt!
• Keep a safe distance from major coolant leaks. It can be so cold that your skin immediately freezes and that causes "burns".