If your car’s air conditioner isn’t working as well as it used to there’s a good chance that it needs to have the refrigerant topped off. But before you can do that you’ll need to know how to drain the refrigerant from the system. This process is actually quite simple and with a few tools and a little know-how you can do it yourself.
Here’s what you’ll need:
• A set of wrenches
• A socket set
• A screwdriver
• A catch pan
• A pair of gloves
• Safety goggles
Before you get started make sure that your car is parked in a well-ventilated area. You’ll also want to put on your gloves and safety goggles to protect yourself from the chemicals involved.
Once you’re all set up locate the low pressure service port on your car. This is usually located on the larger of the two pipes that run from the compressor to the condenser. The low pressure service port will have a cap with a Schrader valve which is similar to a tire valve.
Using your wrench unscrew the cap from the valve and let the pressure out of the system. You may hear a hissing noise as the pressure is released. Once the pressure is relieved remove the cap entirely.
Next use your socket set to remove the bolts that hold the compressor in place. Once the bolts are removed you can carefully disconnect the compressor from the rest of the system. Make sure that you have a catch pan ready because some of the refrigerant may leak out as you disconnect the compressor.
Once the compressor is disconnected you can remove the bolts that hold the condenser in place. The condenser is the large radiator-like component that is located in front of the engine. Be careful when removing the condenser as it may be fragile and could be damaged easily.
With the condenser removed you should be able to see the evaporator. The evaporator is located inside the passenger compartment behind the dash. You’ll need to remove the dash to get to the evaporator so be careful not to break anything.
Once the dash is removed you can use your screwdriver to remove the screws that hold the evaporator in place. With the evaporator removed you can drain the refrigerant into your catch pan.
Finally use your wrench to remove the bolts that hold the receiver-drier in place. The receiver-drier is located near the condenser and it contains a filter that helps to remove impurities from the refrigerant.
With the receiver-drier removed you can drain the last of the refrigerant into your catch pan. Once all of the refrigerant has been drained you can proceed with recharging the system.
How do you properly drain refrigerant from a car’s AC unit?
You’ll need to locate the low pressure service port to begin.
Once you’ve found it attach your refrigerant recovery machine.
Start the car and turn the AC on to the highest setting.
Let the machine do its work until it’s full.
Finally turn off the machine and the car.
Where is the low pressure service port on a car AC unit?
It’s usually located near the evaporator.
On many vehicles it will be labeled with a “L” for low pressure.
What does a refrigerant recovery machine do?
It’s used to recycle the refrigerant in the AC unit so it can be reused.
How do you know when the refrigerant recovery machine is full?
There will be a full line on the machine that you’ll need to watch.
Once the line is reached turn off the machine.
After the refrigerant is drained what do you need to do?
You’ll need to properly dispose of the used refrigerant.
Be sure to check your local laws on how to do this.
How often should you drain the refrigerant from your car AC unit?
There’s no set time frame but it’s generally recommended to do it every two years or so.
Can I do this myself or do I need to take it to a mechanic?
You can do it yourself if you have the proper tools and knowledge.
Otherwise it’s best to take it to a mechanic.
What are the consequences of not draining the refrigerant from my car AC unit?
The refrigerant will degrade over time and eventually turn into a gas.
This gas can cause the compressor to fail.
How much does it cost to have a mechanic drain the refrigerant from my car AC unit?
It typically costs around $100.
Is there anything else I need to do after the refrigerant is drained?
You’ll need to properly dispose of the used refrigerant.
Be sure to check your local laws on how to do this.
Can I just put new refrigerant in without draining the old?
No you’ll need to properly drain the old refrigerant first.
Do I need any special tools to drain the refrigerant from my car AC unit?
Yes you’ll need a refrigerant recovery machine.
How long does it take to drain the refrigerant from a car AC unit?
It typically takes around 30 minutes.
What is the best time of year to drain the refrigerant from my car AC unit?
It’s typically best to do it in the spring or fall.
What is the worst time of year to drain the refrigerant from my car AC unit?
It’s typically best to avoid doing it in the middle of summer or winter.
