You might suspect your car AC is overfilled. But how do you determine?
In reality, there’s no way to know for certain apart from visiting an AC technician. They’ll use the appropriate (legal) equipment to check and top up your refrigerant levels.
Your car’s air conditioning needs just the right amount (and type) of refrigerant. Surplus refrigerant will put too much pressure on the system, reducing its effectiveness.
Always remember that you should never work on your car’s air conditioning at home. This isn’t a task you can DIY. It’s illegal and too intricate to get right without the proper equipment. You’ll damage your system.
This guide explains what you need to do if you notice signs of an overcharged AC.
Let’s plunge into it!
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How Does The AC System Work?
There’s no need for too much detail here. However, you should be aware of the basic principles of air conditioning. Essential knowledge will help you understand why overcharging AC systems lead to the symptoms mentioned below.
Refrigerant is a gas (in its natural form). There are three in use today, although almost all on the road take R-134a or R-1234yf (which all new cars have):
- R-1234yf (2015/2016 cars and onwards) – “2,3,3,3-Tetrafluoropropene”
- R-134a (mid-1990s to 2015) – “1,1,1,2-Tetrafluoroethane”
- R-12 (older vehicles) – “Dichlorodifluoromethane” – also known as Freon, and now illegal to use.
You can’t blend refrigerants. So if your car takes R-134a, you can’t put R-1234yf in it.
It’s contained in a series of high-pressure and low-pressure tubes. You can see a couple of these when you open the hood.
The gas is compressed and pushed through these pipes by a compressor. In ICE cars, this is propelled by the engine’s crankshaft via the serpentine drive belt.
The refrigerant passes through the condenser (“hot side”) and evaporator (“cold side”). Through this process and changing between high- and reduced-pressure gas and liquid states, the heat and moisture are removed from your cabin.
Simply put, that’s how your vehicle’s cooling system functions!
Now, imagine there’s too much gas in the system. There’s too much pressure, putting undue strain on the compressor. It then can’t push the refrigerant through so efficiently. As a result, the condenser, evaporator, and all the other components won’t work properly.
Why Is My Car AC Overcharged?
A proficient AC technician shouldn’t ever overcharge your system.
They use specialized equipment that fill your car with exactly the right amount of refrigerant. Before topping your vehicle up, they’ll take data straight from the manual to ensure it’s accurate.
After all, if they over- or undercharge your AC and it doesn’t cool the ambiance, you won’t be returning, will you?
Of course, it’s always possible that a technician is having a difficult day. However, the more likely problem is that someone has tried a DIY air conditioning top-up.
First of all, that’s almost certainly illegal. You must be qualified as an air conditioning refrigerant handler to work with AC refrigerant. That might seem excessive, but this stuff is extremely bad for the environment.
Second, any trained AC technician will know to use the proper equipment, quantity, and materials. So, even if a skilled person were to work at home, they wouldn’t use a DIY kit.
The air conditioning refrigerant machines that shops use cost thousands. That’s partly why a re-gas is so expensive (the cost of gas and oil is also pricey). Why would you use a $10 knock-off from Amazon? It won’t do the job adequately.
Symptoms Of An Overcharged Car AC
Here are some of the most common symptoms of an overcharged automotive air conditioning unit.
In short, you can expect your air conditioning to stop working efficiently.
Warm Air Coming Out Of The Vents
On a sultry day, your car’s air conditioning may not be capable of cooling the air entering your vehicle. But don’t worry, air will still circulate unless there’s a problem with your vents or fans.
How poor the cooling effect depends on how overcharged your AC is. The larger the quantity of refrigerant beyond the normal level, the less heat will be removed from the air.
At a technical level, the heat transfer rate in the condenser and evaporator is reduced. It can’t exchange as much heat/cool with the air.
As a result, it’ll still feel warm, even if you turn the temperature down to its lowest setting.
This only applies on sweltering summer days. The air might be cool in other seasons – it doesn’t need much additional temperature reduction.
Humid Air Coming Out Of The Vents
Do you live in a humid part of the world, such as Florida? If so, you’ll be able to feel the difference between “normal” air and what comes through your AC.
The air conditioning in your car also removes moisture via the cooling fins of the evaporator.
You might notice that the air coming through the vents is more damp than usual, even with the AC on.
Again, this issue happens because the refrigerant isn’t being circulated around the system efficiently. It doesn’t get so frigid, so the moisture doesn’t condense into water droplets.
Broken Or Breaking AC Compressor
There could be several signs of a faulty AC compressor in your car.
- Pressing the AC button to engage the electromagnetic clutch might result in ominous noises.
- Wear on the serpentine drive belt.
- A broken serpentine drive belt.
The compressor pressurizes refrigerant into a high-pressure gas. It sends it to the condenser, turning it into a high-pressure liquid.
It might break if the compressor can’t “compress” the refrigerant enough (because the AC has been overcharged and there’s too much in it). It certainly won’t operate at optimal efficiency.
If the compressor fails, your AC is essentially useless. It can’t do anything.
Thus, an overcharged AC could completely break the system.
How To Tell If AC Is Overcharged
You might notice some of the above symptoms. However, it doesn’t necessarily mean you have an excessive AC.
For example, if the compressor breaks (due to wear), it would result in exactly the same symptoms. An undercharged AC would also have the identical effect as a leak.
What is the optimal way to tell if your AC is overcharged? Go to a mechanic.
They’ll hook your car up to the apparatus and read the pressure gauges. This means they can instantly tell you what’s wrong – and then fix it.
How Do You Fix An Overcharged AC?
The fix for an overfilled AC is straightforward. Go to a mechanic and get the system re-gassed.
A re-gas should come to around $150. Factors that might affect the price include the refrigerant type, quantity, and oil volume.
The technicians will re-gas it to the level it was intended for. You should then be able to utilize it as usual.
Regrettably, they may discover your exorbitantly priced AC has caused additional problems. For instance, the compressor might be damaged.
In this case, you’ll also need to pay for replacement components. This specific job (the compressor) could come to about $900 but would include the flush and re-gas.
You will need to see an air conditioning specialist for major issues like leaks.