• Billy Hillmuth

Why Shouldn't You Recharge Your Car AC Yourself?

There's nothing as frustrating as driving around in a car with a broken air conditioner. But, before buying a can of Freon and doing it myself, I needed to know, 'should I recharge the AC myself?'

A vehicle's air conditioning is a closed system, which means it is airtight. The refrigerant shouldn't escape unless there is an underlying problem. Unless the AC system needs repair, you shouldn't have to recharge it.

Using a DIY AC recharge kit may delay a trip to a professional as the problem worsens or make things worse by overcharging. Let's look at the AC recharging process and why AC recharge kits don't cut it.

What Does Recharging AC In A Car Mean?

Recharging is replacing refrigerant that's leaked out of the car's air conditioning unit. If your vehicle's AC has low pressure and is blowing warm air, it means there is a leak because it is a sealed system.



An R-134a refrigerant leak allows entry of moisture and air, which can damage the AC compressor when combined with the refrigerant.

Can I Do An AC System Recharge Myself?

Yes, you can, but you shouldn't. The recharge process is oversimplified by bloggers and YouTubers. You need technical knowledge and tools that only a local auto repair shop has for a successful recharge. Plus, there are some risks in DIY AC system recharging.

DIY charging doesn't remove old refrigerant - Your car's AC needs recharging because the refrigerant has leaked out of the system, resulting in low pressure. Ideally, leaking shouldn't happen. However, some cars leak small amounts of refrigerant and need the system recharged after several years.

Unfortunately, you cannot be sure how much refrigerant is left in the system with recharge kits. You can overcharge the AC system and cause notable damage to the various components like the condenser.

For an efficient recharge, you must first clean out the remaining refrigerant, moisture, and contaminants in the system. A certified mechanic should perform this service. Then, once the AC system is clean, they'll fill it with fresh refrigerant correctly and in the proper amounts.

DIY recharging kits don't work on some cars - Many AC recharger cans are filled with R-134a refrigerant. R-134a is the most common refrigerant in vehicles today. However, vehicles built before 1995 use R-12 (Freon) refrigerant, which was discontinued for its effects on the ozone layer. New hybrid and electric cars use the R-123yf refrigerant, which has become the new standard for AC systems.


The new R-123yf refrigerant is about five times more costly than R-134a and does require additional equipment. There's no retrofit in any of these systems with each other anymore.

When recharging a car's AC system, you cannot mix the refrigerants. Adding the wrong refrigerant into the AC system will undoubtedly damage the AC parts.

DIY recharging doesn't measure by weight - After emptying the air conditioner system, our professionals will determine how much refrigerant they should add to the car's AC system. Manufacturers stipulate how much refrigerant should be recharged by weight, usually in oz. or lbs.

Usually, recharge cans have simplified pressure gauges. However, getting the correct pressure gauge reading is no guarantee of correct refrigerant weight. Moreover, recharge cans only measure pressure on the lower side, which increases the chances of overcharging the system. When the system is overcharged, you risk blowing the air conditioning hose or damaging the compressor, which will cost thousands in repairs.

Note: The pressure on the low side should be between 35 and 45 psi, and the gauge on the high side should be reading between 200 and 400 psi. If the pressure gauge on the low side reads over 45 psi, the system is overcharged, or a component is faulty.

Car AC System Blowing Warm Air

If you wake up to an AC blowing warm air instead of cold air, it's due to severe leakage. For this, you'll need to have a professional find the leak and fix it before topping up the refrigerant. While some DIY recharge cans contain seal leak compounds (and compressor oil) to fix small leaks, larger leaks remain unattended.

At Hillmuth Auto Care, we have specialized repair equipment that helps our professionals locate leaks in the AC system to repair them and prevent the problems from reoccurring.

Are Air Conditioner Recharge Kits Bad?

Fundamentally, recharge kits are not bad. However, they often do more harm than good. They are designed with a stop leak which plugs small leaks as the refrigerant and compressor oil run through the system.

Unfortunately, this method can easily clog the air conditioner components like the pump, hose, and compressor. Recharge cans make it easy for you to overfill the air conditioning system and cause bigger problems.

Are Air Conditioning Recharge Kits Worth It?

No, they are not because they don't fix broken AC systems. Instead, they simply recharge refrigerant and leave the cause of the problem unattended. So while a recharge may get cool air blowing again, it masks the real issue as it worsens. Eventually, you may end up fixing a leak, replacing damaged components, and recharging the AC system.

What Is Better DIY or Professional AC Service?

While you could go the DIY route and most likely save some money short term, you may end up spending thousands in the near future. So instead of fixing it yourself, we recommend having an ASE-certified mechanic diagnose and repair the AC system.

At Hillmuth Auto Care, we aim to keep your vehicle in tip-top shape with timely and quality repairs. So contact us today at (410) 850-8055, and we will find the problem in your AC system, answer any questions you may have, and fix it.


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