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This is a relatively common problem in most cars with air conditioning. The likelihood is that you will experience something like that at least once or twice in your time driving. There are several possible reasons for this happening. We will go through a few of them here!
With air conditioning units, it’s usually best to get a professional to look at them. You can go one step beyond your general mechanic as well, looking specifically for a car air conditioning specialist. This professional will give you the best chance possible of getting your AC up and running again.
What’s Causing It?
Let’s start with the basics.
If your AC is blowing out hot (or warm) air, it’s not working properly. There is a problem. It’s not just a “one of those things,” and it is (usually!) possible to get it fixed.
There could be one of a few different things wrong with your air conditioning system. In this article, we will quickly go through a couple of things that may be causing you your problems.
How Does a Car AC Unit Work?
To answer the question “What’s Causing It?”, it may be useful to very quickly explain how an air conditioning unit works in a car. We will do this in extremely basic terms for conciseness.
Contrary to what you might think, an air conditioning unit doesn’t just blow out cold air. It’s actually a little bit cleverer than that. Your air conditioning system takes in hot air and removes the humidity and heat, returning the air in a dryer, cleaner way. This is what makes your air conditioning feel so good on a hot summer’s day.
Air conditioning systems are essentially systems of pipes filled with refrigerant gas. In modern cars, gas R134a is used. Up until 1993, the standard air conditioning refrigerant was a chemical called R12. From 1994 and onwards, all new cars had air conditioning systems that used R134a, as it was found to be much less damaging to the environment if it leaked.
There are several components, most of which aren’t worth going into much detail on for now, but there are two that are worth knowing about. These are the condenser and the compressor.
Potential Causes of Your Problem
In short, the job of the condenser is to remove heat from the refrigerant as it flows through the system. It looks a little bit like a small household radiator with some fans to help with the cooling process.
If anything goes wrong with the condenser, you will likely get a result of hot air blowing out the vents at you. Potential problems could be a blockage or a leak. Both of these would result in the refrigerant not cooling properly – rather, it would flow by, staying hot, and resulting in hot air coming out of your vents.
Likewise, if the cooling fans on the condenser are not working, the refrigerant will not be being cooled effectively. Cooling fans are known for being quite flimsy, and they can break off or stop working.
A compressor drives air conditioning units on combustion engines. This compressor is turned by a pulley that is attached to the drive belt. This is the belt you can see when you open the hood of the car. There are usually several other pulleys on there that might include a tensioner, crankshaft, power steering pump, alternator, and so on.
By following the air conditioning pipes to it, you can identify the compressor. If you’re struggling to find it, use a search engine to find a diagram of your specific car’s drive belt. For example, if you drive a 2004 Crown Victoria, type in “2004 Ford Crown Victoria drive belt diagram”. This should give you a diagram showing you what all the pulleys are. The air conditioning pulley will likely be identifiable by an “AC” label.
If the compressor isn’t doing its job, the refrigerant won’t be being pumped around. Air will still blow out of your vents, but it certainly won’t be cold.
There are several possible causes of a faulty compressor. There could be a fault with the pulley, with your drive belt tension, or some internal fault within the compressor itself.
The AC System Pipes
Another possible fault you might get is a leak from the pipes in your air conditioning system.
Could it Be a Possible Electrical Problem?
It’s possible. Different parts of the system require an electrical charge to function.
You may be able to inspect some of the wiring yourself, but if in doubt, then it’s a wise idea to get an auto electrician out to have a look for you.
Another common cause can be if your refrigerant levels are low. This could be due to a variety of reasons, such as not enough being put in at the last service.
If there isn’t enough refrigerant in your system, it will be less able to transfer the heat away from the car effectively. This will result in the air blowing out from your vents being hotter. If you suspect this to be the problem, you can get an air conditioning system re-gas from most garages. Make sure it’s a reputable one, though, and that they use the correct refrigerant. Some garages have been known to put cheaper things into your system to save themselves money at your expense.
Rubber seals can become brittle, especially if the air conditioning isn’t used over a long period, such as through winter. This can cause a leak.
So What Do I Do to Fix it?
Regrettably, with almost every air conditioning fault, you are going to need professional help.
The main reason for this is, apart from these units being incredibly sensitive and needing specialist equipment, there is a fine for releasing refrigerant into the atmosphere. It’s extremely bad for the environment (1300 times worse than carbon dioxide), and not to mention toxic to you.
The only ones of these problems that you may be able to look at yourself are electrical problems and problems with the pulleys on your drive belt.
Unfortunately, with AC systems, we would always recommend contacting a specialist to do the work for you. This will be expensive, but it’s certainly worth it to get that cool, crisp air back in your car.
As with everything, it’s much easier (and much cheaper) to prevent this problem from occurring in the first place, rather than fixing it when it does happen.
To look after your air conditioning system, the best thing to do, to begin with, is to get it serviced from a reputable specialist. After this, to keep your AC healthy, the most effective thing to do is to leave it on as much as possible. Even throughout winter, once your car has warmed up, you should turn on your AC – even if the fan is on the “0” setting and the temperature gauge set to hot.
Keeping your air conditioning system working will keep everything lubricated and, therefore, it’s less likely to stop working.