AC Overcharged – Symptoms, Causes, and Fixes

Summer is the time of year when people tend to use their air conditioners the most. It sure is a real lifesaver during those hot and humid days.

You’ve just charged the AC system at home to prepare for the hot summer days, but you notice the car AC not blowing cold air. This can be frustrating and can quickly ruin your day.

So in this article we’ll discuss the symptoms of an overcharged AC, what the possible causes are, and how to fix it!

Symptoms of an Overcharged AC

The symptoms of an overcharged AC are that the vents blow hot air, have reduced airflow, the check engine light is on, or the compressor mounted to the engine is noisy. Likely, the AC is overcharged at home and should be corrected by a mechanic that can withdraw the toxic refrigerant without releasing it into the air.

If you notice any of these issues, it’s time to take a look at your AC unit

1. Insufficient Cooling

One of the first and most common symptoms that your AC overcharged is insufficient cooling and if the AC is performing worse than before the refill.

This can be caused for a variety of reasons, but the most common is that the AC unit is low on refrigerant, or even overcharged.

When this happens, your AC will struggle to cool your vehicle cabin, and you’ll likely notice the vents also perform poorly, barely blowing air at maximum power.

2. Lack of Airflow

Another symptom that your AC is overcharged is a lack of airflow in the vehicle’s vents.

The AC does not engage immediately when you cold start your vehicle. Instead, it slowly ramps up over time.

If the AC is not performing as expected after a few minutes you should turn the AC off to avoid damaging the AC system as the AC is likely overcharged.

If you happen to notice a sudden decrease in airflow from your vents, this is likely due to an overcharged AC system.

When the AC is overcharged, the compressor will run continuously in an attempt to cool the cabin, which prevents airflow from reaching the vents.

This can cause the AC to blow warm air and reduce the amount of airflow in your vehicle significantly.

This in turn could cause the AC compressor to fail which could cause the serpentine belt to fail as well, leading to eventual costly repairs if you keep driving the car if that happens.

It’s noteworthy that a sudden drop in airflow also could be caused by a clogged cabin filter, so be sure to check that as well!

3. Compressor Noise

Another symptom of an overcharged AC is compressor noise.

The compressor is the heart of the AC system, and when it’s overworked, it can start to make strange noises.

If you hear a loud, continuous noise coming from under the hood after an AC recharge, the compressor has likely failed due to an AC overcharge.

If you keep driving with a faulty compressor the serpentine belt could break which could cause severe damage to your car.

Strange sounds coming from the engine bay are never a good sign, so be sure to get the car checked out if you hear any weird noises!

Overcharged AC Causes

There are a few possible causes of an overcharged AC.

The most common cause is not knowing how much refrigerant is supposed to be added to the system when refilling the AC at home using cheap refill cans purchased from Amazon or your local parts store.

1. Not Knowing How Much Refrigerant to Add

The most common cause of an overcharged AC is not knowing how much refrigerant to add when refilling the system.

When adding refrigerant, it’s important to only add the amount that is specified by the manufacturer.

Each brand, model, and year of the car has a specific amount of refrigerant that needs to be added.

Simply watching a DIY guide on Youtube and following their instructions is not research enough to refill the AC at home.

Be sure to do the research for your specific make and model before adding refrigerant to your vehicle’s AC system.

2. Faulty Refill Gauge

Another potential cause of an overcharged AC is using a faulty refill gauge on the refill tube.

When adding refrigerant, it’s important to use an accurate quality gauge.

If the gauge is not accurate, it’s possible to add too much refrigerant which will lead to an overcharged AC system.

Faulty gauges are one of the most common causes of an overcharged AC system.

3. Wrong Refrigerant Added

Another potential cause of an overcharged AC is adding the wrong type of refrigerant to the system.

There are a few different types of refrigerants, and each type has a different purpose.

If the wrong type of refrigerant is added, it can cause the system to overcharge and eventually fail.

Be sure to use the correct type of refrigerant specified by the manufacturer to avoid this potential issue.

How to Fix an Overcharged AC

Mechanic Fixing an Overcharged AC

Fixing an overcharged AC is a fairly simple process, but it’s important to take your car to a professional mechanic to have the AC system serviced.

At the mechanic, they will use a special AC recovery machine and properly bleed the system of any excess refrigerant and refill it with the correct amount specified by the manufacturer.

Once the system has been properly bled of excess refrigerant, the AC will work as normal and should not have any issues going forward.

Can I Bleed the AC at Home?

If you think your AC may be overcharged, the best thing to do is take it to a professional mechanic and have them check it out.

Attempting to fix an AC system at home is not recommended as it can be dangerous and lead to further damage if not done correctly.

Not only that, freon is a health and environmental hazard. Freon is a deadly poisonous substance, thus any freon leaks should be dealt with by an expert air conditioning repair technician.

Autos Pack is all about DIY repairs and diagnostics, but when it comes to AC refrigerants such as Freon, we recommend you let a certified mechanic handle it.

They have the proper equipment to safely and correctly check, diagnose, and fix your overcharged AC system.

How to Prevent Overcharging the AC

The best way to prevent an overcharged AC is to take your car to a professional mechanic and have them service the system.

Mechanics that service AC systems got special tools, as mentioned, to properly refill the AC refrigerant.

Using DIY methods to refill the AC at home can lead to overcharging the system as it’s difficult to know how much refrigerant needs to be added.

The Cost of Recharging or Bleeding an AC System

The cost of recharging or bleeding the AC system is pretty much the same as the mechanic bleeding the system needs to fully extract the refrigerant before adding the correct amount.

The cost is usually $100 to $250, so I recommend visiting a mechanic directly instead of recharging your AC at home.

How Often Do I Need to Recharge the AC?

You should recharge the AC every two to three years or so to maintain optimal performance. This, of course, depends on how much you use your AC and if there are any leaks.

Over time, the AC system will slowly lose effect causing the AC not to blow cold air as it once did.

Recharging the AC will restore the cold air blowing and keep your car comfortable during those hot summer days.

Checking the AC system for leaks is quite tricky as you need to add UV dye to the AC system and check for leaks using ultraviolet light.

Can You Recharge the AC by Yourself?

As I’ve said earlier, we don’t recommend recharging the AC by yourself as it can be dangerous and you may overcharge the system.

But, of course, you could try it if you want. Just be sure to follow the instructions properly, use the correct type of refrigerant, and don’t overcharge the system.

If you’re not comfortable doing it yourself, then take your car to a professional mechanic and have them do it for you. It’s really not that expensive and they’ll be able to properly check for any leaks in the system.


What Happens When You Overfill AC Refrigerant?

Overfilling the AC refrigerant can cause the compressor to break down. It can also lead to leaks in the system as well as other problems, such as the vents blowing hot air.

What Is the Correct Amount of Freon for an AC Unit?

The correct amount of Freon for an AC unit is specified by the manufacturer. You should always consult the manufacturer’s instructions before adding refrigerant to the system.


Overcharging the AC could lead to a hot cabin on hot summer days, and eventually system failure.

If you think your AC may be overcharged, take it to a professional mechanic and have them check it out.

They have the proper equipment to safely and correctly check, diagnose, and fix your overcharged AC system.

Photo of author

Robin Söder

Robin has always been passionate about cars ever since young age. Over the years, Robin has worked on thousands of cars and gained invaluable experience in the process. He is considered an expert in his field and is often consulted by other mechanics for advice.

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