How to Recharge Your Car Air Conditioning

Schedule Car AC Repair
Service Area

$205.38 - $221.01

Price range for all vehicles
Average rating from 416 customers who received a AC Recharge.

When your car’s air conditioning (AC) begins to lose power and doesn’t blow cool air, it may be time for an AC recharge. Recharging your AC means adding more refrigerant to your AC system to allow the air to start blowing cold again.

Important to know: recharging your AC is a temporary fix to a likely bigger problem. If your system is indeed missing refrigerant, your air conditioning system has a leak and needs to be inspected and repaired with a certified mechanic. Refrigerant does not evaporate in an airtight system, so air must be leaking in.

  • Note: Some older vehicles cannot have their AC unit recharged. These vehicles generally fall before the year 1995 and use an R12 refrigerant no longer made. The only option is AC replacement.

Though an ac recharge can be completed at home, it is still considered a more professional repair, as it contains work with hazardous liquid and is best left for a certified mechanic.

Recharge your AC in 7 easy steps:

Because of the sensitivity of this procedure, we will explain how to use the AC recharge kits. They have shown to be the most effective and safest option in comparison to trying to repeat a mechanic’s role at home.

Materials Needed:

  • AC dispenser with trigger and low side gauge
  • Meat thermometer
  • Refrigerant (12-28 ounces, depending on vehicle requirement. This information is located on the underside of the hood).
  • Safety glasses and gloves

  • Tip: Always wear safety glasses when performing work under the hood. It is especially important to be careful to not get any refrigerant on your skin as it freezes quickly and is very painful. Please be sure to follow all instructions that are included with your AC recharge kit and read every canister’s warnings carefully.

Step 1: Turn on your AC. Start your car and turn your AC to Max or High.

Step 2: Determine if AC compressor is engaging. An AC compressor is a device driven by the accessory belt that converts the refrigerant from liquid to gas. The compressor has a clutch at the end of it that should be spinning with the accessory belt when the AC is on high. Look for these pulleys moving.

red arrow pointing to compressor pulley

  • If the clutch on the compressor is indeed engaging, then it is likely that the system is low on refrigerant, especially if the air is still blowing slightly cold. You will still want to move ahead with testing the pressure before adding refrigerant.

  • If the clutch is not engaging the compressor, then the AC system is either very low on refrigerant, there is an electrical problem, or the compressor itself has failed. Adding more refrigerant after pressure testing will allow you to know which of these the cause is.

Step 2: Test the pressure. To test the pressure, turn the vehicle off and locate the low side pressure port. The low side pressure service port is generally located on the passenger side of the engine bay. It will have a black or grey cap on it with the letter “L”.

low side pressure cap

  • Tip: If you are having a hard time finding it, try locating the two aluminum pipes that are coming out of the firewall (the metal wall behind the engine) and trace the larger-diameter pipe until you find the service port.

Step 4: Attach the recharge hose from the kit. To attach the recharge hose, place the quick-connect fitting — found on the end of the recharge hose — over the port and push down firmly until you hear it click into place.

recharge house over port

  • Be careful not to pull the trigger at this time as this will release refrigerant from the AC system into the atmosphere.

Step 5: Restart the vehicle and monitor the gauge. Restart the vehicle and make sure the air conditioner is on the highest settings. Begin to monitor the gauge by watching for the AC compressor to engage the clutch. Once the compressor is engaged, if the low side pressure is under 40 psi, it is verified that the AC system is undercharged. You want the reading to be as close to 40 psi as possible.

low side pressure showing

Step 6: Thread the refrigerant can onto the recharge hose. Threading the can onto the hose allows you to slowly top off the AC system with liquid refrigerant. Once the can is installed, hold the can upright and squeeze the trigger for 5 to 10 seconds to add the refrigerant to the system. After you release the trigger, check the pressure gauge to be sure you are not overcharging the system.

squeezing trigger on refrigerant recharge

  • Proceed until you are as close to 40 psi as possible.

Step 7: Return to the inside of the car and check the temperature. Using a thermometer, insert it into one of the AC vents on the driver’s side, near the steering wheel, and note the temperature. A fully charged system will blow air as cold as 28 degrees. This can vary slightly depending on ambient temperature as well as whether the vehicle has been stationary.

thermometer inside ac vent

  • If the pressure is over 40psi, that is considered “high” low side pressure. This can be caused by overcharging the system or if the compressor itself is malfunctioning. If the pressure is reading high, it is time to seek professional mechanic help, as repairs may be necessary.

You have successfully recharged your AC! Your AC should be running colder now and your drive should be much nicer.

  • Warning: It must be stressed that if your refrigerant was low to begin with, there is little doubt that there is a system leak. AC repairs are highly specialized and this sort of repair needs to be addressed by a professional for proper procedures and practice, as well as keeping the refrigerant from leaking into the atmosphere and polluting the air we breathe.

Next Step

Schedule Car AC Repair

The most popular service booked by readers of this article is Car AC Repair. Yourmechanic’s technicians bring the dealership to you by performing this job at your home or office 7 days a week between 7AM-9PM. We currently cover over 10k cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Car AC Repair reviews

Excellent Rating


YourMechanic Car AC Repair Service

Average Rating

4.9/5

Number of Reviews

416

Rating Summary
391
19
0
2
4
391
19
0
2
4

David

8 years of experience
111 reviews
David
8 years of experience
Chevrolet Cruze - Car AC Repair - Orlando, Florida
David was here before the time, great. First time ever to have my car service at my house, so much easier to deal with one person instead of a garage.
Lincoln Town Car - Car AC Repair - Orlando, Florida
David was pleasant, on time and very well trained. Very informative. Great service. Highly recommend.

Ben

39 years of experience
1117 reviews
Ben
39 years of experience
Mitsubishi Eclipse - Car AC Repair - Houston, Texas
WOW great service .Ben supper friendly he take care my son car AC better than taken it to a shop and you had to wait all day and miss up your plane for the day .these guys they know what the wright thing for your car with honesty.
Mazda 3 - Car AC Repair - Houston, Texas
Ben was able to come to the appointment early to make the repair and did a great job explaining the issue and showing what he did to make the repair. I highly recommend him!

Edmundas

15 years of experience
30 reviews
Edmundas
15 years of experience
Ford Thunderbird - Car AC Repair - Winter Park, Florida
Very knowledgeable, willing to help with ancillary functions, very professional. Explained the details of his findings.
Nissan Altima - Car AC Repair - Oviedo, Florida
Edmundas was extremely professional and went above and beyond expected -- espcially in providing all data and current state of my vehicle. The expereience was great and I would recomend Edmundas to all of my associates. Thank you!

Braxton

9 years of experience
184 reviews
Braxton
9 years of experience
Chevrolet Silverado 1500 - Car AC Repair - Orlando, Florida
On time, courteous, didn’t sell me something I didn’t need, quick and a/c is working great! Would call him again and recommend.
Hyundai Sonata - Car AC Repair - Orlando, Florida
He was great even though it was a repair that could not be done he was helpful about giving me the info I needed

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE