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How to Recharge the Air Condition in Your Car


It can be required to recharge the air conditioning system with fresh refrigerant if it starts to lose its ability to cool effectively. For instructions on how to recharge the A/C system when it is low on pressure or has been cleaned out after a repair, as well as a chart showing R-134a A/C pressure, continue reading.


Do not charge the car if the air temperature is 55 °F or below. Additionally, using a charging hose with a gauge is always advised. According to the temperature of the surrounding air, a chart similar to the one below should be included on the refrigerant package to show what pressure to charge the system with. Use the A/C pressure chart below this list as a general reference if a chart is not given. Additionally, the suggested pressures for various AC systems might vary, so it is worthwhile to search in a maintenance manual or online to find the correct pressure for your car.

These recommendations will guarantee that the system can perform well when you recharge it. A single gauge linked to the refrigerant can be used to charge an AC system, but it is usually advised to utilize a full set of manifold gauges to monitor both the high and low side pressures. Start the car now, and make sure the air conditioning is on the level of the MA Locate the AC compressor for the car as a point of reference and keep an eye on the AC clutch.

The pulley only rotates on the exterior while the AC compressor is deactivated. The whole clutch assembly will rotate once it is engaged, driving the compressor. When refrigerant pressures or volume are too low, your compressor is programmed not to operate at all.

Usually, the line that connects the accumulator and compressor has this port. The largest of the two fittings, the high side fitting is situated between the AC compressor and condenser. To confirm the precise placement of the low-side service port, see the service manual. You should utilize the low side when connecting a can of refrigerant to a car using a single hose or gauge. Both will be used if you are mounting a set of gauges on the car.

If the car being repaired still uses R12, it must be evacuated and refitted because R12 was often used as the original refrigerant in vehicles manufactured in 1994 and before. It is forbidden to combine R12 with any other refrigerant. Never put refrigerant through the high-side port; doing so is extremely risky and might result in injury. When the hose screws on to attach, you will immediately identify an R12 type fitting because it resembles a tire valve, while an R134A fitting is a bigger quick-connect. Additionally, starting in 2013, a lot of automobiles started using 1234YF refrigerant. Because this refrigerant is incompatible with R134A, only an expert should troubleshoot it.

After cleaning off any dust with a clean rag, open the low-side service port's cap.

Make a secure connection by attaching the charging hose to the low-side service port. If the hose is difficult to attach, you could be using the incorrect port. If using a set of gauges, attach them to both.

Add refrigerant to the system as directed on the refrigerant packaging.

Use the table for ambient air pressure to determine the proper pressures, and then while the system is charging, continuously check the pressure readings. Your AC compressor clutch will not engage if the system was low. The compressor clutch should activate after the low-side pressure hits around 25 to 30 PSI.

As additional refrigerant is added, you could observe the compressor clutch engage and disengage. Eventually, it needs to continue to be active constantly. It is crucial to stress that overcharging the system will result in long-term harm. You should seek the assistance of a qualified mechanic in your area if you are unclear about the pressure or volume of refrigerant in your system at the moment.

Remove the charging hose from the low-side service port (or gauges) once the air conditioner has been charged to the appropriate pressure. Keep the can connected to the charge hose, and store any extra refrigerant in a cold, dry place.

Make that there are no tears, nicks, or fractures in the seal that is underneath the cap. If a leak ever developed in the Schrader valve, this seal could provide additional security.

R-134a Temperature Pressure Chart (Tabla de Temperaturas y Lecturas)

​Ambient Temperature °F/°C

(Temperatura Ambiental)

Low-Pressure Gauge (Service Port on the Side of Low pressure)

High-Pressure Gauge

(Service Port on the Side of High pressure)

65°F (18°C)

70°F (21°C)

75°F (24°C)

80°F (27°C)

85°F (29°C)

90°F (32°C)

95°F (35°C)

100°F (38°C)

105°F (41°C)

110°F (43°C)

25-35 psi / 172-241 kPa

35-40 psi / 241-276 kPa

35-45 psi / 241-310 kPa

40-50 psi / 276-345 kPa

45-55 psi / 310-379 kPa

45-55 psi / 310-379 kPa

45-55 psi / 310-379 kPa

45-55 psi / 310-379 kPa

45-55 psi / 310-379 kPa

45-55 psi / 310-379 kPa

135-155 psi /931-1069 kPa

145-160 psi / 1000-1103 kPa

150-170 psi / 1034-1172 kPa

175-210 psi / 1207-1448 kPa

225-250 psi / 1551-1724 kPa

250-270 psi / 1724-1862 kPa

275-300 psi / 1896-2068 kPa

315-325 psi / 2172-2241

330-335 psi / 2275-2310 kPa

340-345 psi / 2344-2379 kPa

Ambient temp is the outside atmospheric temperature.

Your air conditioner should perform better right away after being recharged. After recharging, it can be worthwhile to check the pressure a couple of times in case the low refrigerant level was brought on by a leak in the system. Get a UV lamp and some UV dye if you think there is a leak so you can detect it. When the UV light is shone upon the A/C components, the UV dye will make the hole apparent.

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Rated 5 out of 5 stars.

I appreciated the professionalism of the HVAC Contractor Sunrise technicians who recharged my car's air conditioning. They explained the process clearly and answered all my questions.

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