Repairing a Leak in Your Car’s AC System Is an Advanced Project for Most DIYers.
- DIY Difficulty Level: Advanced
- Time Required: Several hours
What Is an AC Leak?
It’s an awful feeling when warm weather finally arrives, you turn your car’s air conditioner on for the first time this year, and get nothing but a face full of hot air. Your AC system has sprung a leak, allowing its refrigerant to escape, so it no longer keeps you cool.
A car’s AC consists of several major components:
- Thermal expansion valve
Metal lines or rubber hoses connect all of these components together and keep the refrigerant flowing between them. Most often, the leak is in one of the rubber seals or O-rings that connect the lines and components together. Rubber dries out as it ages, cracks, and can cause a leak. This leak can be practically anywhere in the AC system.
Sometimes it’s possible to recharge your AC and fix a small leak this way. The recharge kit contains a small amount of sealant mixed with the refrigerant. This sealant works its way into tiny cracks as it runs through the system and plugs them up if they’re not too big, enabling your AC to work again. If it’s more than a small leak, though, further diagnosis and repair will be required.
Is It Safe To Drive With an AC Leak in a Car?
Yes, it is safe to drive with an AC leak in your car. You won’t have cold air, but a broken AC won’t hurt any other systems in your car. After your car has been sitting in the sun, you can still open the windows and turn on the fan to cool it down to the same temperature as it is outside. Your heater will still work, as well.
Most modern vehicles will automatically disable the AC compressor if low or no pressure in the system is detected, preventing further damage to the individual components of the system. You should still avoid turning it on, though, just to be sure.
When To Fix AC Leak in Your Car
Your AC system does not require regular maintenance like other components. It’s a sealed system and only requires repair when that seal is broken. Over years, you may notice your AC not blowing as cold air as it used to. A tiny amount of refrigerant might be escaping through a tiny leak to cause this. Now is the time to try recharging your AC, before the problem gets any worse.
What Are Common Symptoms Indicating You Need To Fix an AC Leak in a Car?
The most obvious sign that you have an AC problem is that it’s not blowing cold air out the vents. Other signs of a problem include:
- Knocking noises that could indicate a lack of lubrication
- The smell of refrigerant or any other unusual odor coming out of the vents
- Low pressure in the AC lines (as measured with a recharge kit)
- Hissing sounds that would indicate a refrigerant leak
How To Recharge Your AC
We have a more detailed article all about how to recharge your AC. To summarize:
Step 1: Buy an AC Recharge Kit.
Most auto part stores sell recharge kits for under $50. You can also conveniently purchase them online and have them shipped right to your door.
Step 2: Start Your Engine and Turn On Your AC.
Start your vehicle’s engine and turn on your air conditioner to its maximum setting. Turn your temperature to its coldest setting. If you have separate controls for the rear seats, crank them up as well to get the sealant into every crevice.
Step 3: Connect the Hose
Your can of refrigerant will have a hose with a value at the end. Connect that value to your AC’s low-pressure service port. It’s generally between the air compressor and the evaporator. Your recharge kit is specifically designed to only connect to the low-pressure port, not the high-pressure port, for safety reasons.
Step 4: Open the Valve and Release the Refrigerant
Next, break the can’s seal and allow the refrigerant to flow into your vehicle’s AC system. Keep an eye on the pressure gauge to ensure it stays in the green zone, and listen for your compressor to engage. That’s a good sign that your AC system is working correctly again.
Step 5: Remove Hose From Port
Once you’ve emptied the refrigerant can to fix the AC leak in your car, close the valve and remove the hose from the port. Hop inside to see if cold air is coming out of your vents.
What If a Recharge Doesn’t Work?
If a home recharge doesn’t fix the problem, this is a job best left to the professionals. There are many parts to the AC system, and leaks and holes can exist in any of them. Diagnosis can be a long, difficult process for the DIYer.
A shop will also have the specialized equipment required to diagnose and repair an AC leak. One such piece of equipment runs a special dye through your AC system. This dye will leak out the same holes in the system as the refrigerant, marking them and making them much easier to find. According to RepairPal, an AC leak inspection should cost between $53 and $67, which is a small price to pay to save yourself time and trouble.
A mechanic also has the specialized equipment necessary to properly evacuate and recharge a car’s AC system. A lift enables them to get underneath the car easily, and they know exactly how to disassemble and replace individual lines and components of the AC system once they’ve identified the source of the leak. The cost of the repair itself will depend on exactly what parts need to be replaced.
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Disclaimer: The guidelines in this story are general and not meant to replace instructions for your specific vehicle. Please consult your owner’s manual or repair guide before attempting repairs.
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