How to Recharge Your Car's Air Conditioner

Introduction:
Is the air coming from the vents in your car just not as cold as it used to be? You've likely run low on refrigerant in your A/C system.
Over time, tiny amounts of refrigerant leak from the lines, degrading A/C performance. The solution is simple - put more back in.

Recharging your air conditioner yourself is inexpensive and can be completed in just a few minutes. This is one of the most quick and easy tasks to perform when maintaining a vehicle, but holds the potential to cause problems with the air conditioning system if done incorrectly, so read each step very carefully before proceeding. When finished, your air conditioner should make icy cold air, and  the whole process should only set you back about  25-35 dollars and 15 minutes of your time.

This guide will contain information on how to recharge your air conditioner with refrigerant 134a or r-134a.


How Air Conditioners Work:
An air conditioner has three main parts. A condenser, a compressor, and an evaporator. The condenser and evaporator are, more or less, two radiators connected in a loop. The compressor is situated between them on one side of the loop. The system is sealed from the outside, and filled with a working fluid, in this case r-134a. The compressor takes low pressure, gaseous, r-134a, compresses it (which creates heat), then sends it to the condenser, where the heat is dissipated to the outside. After the condenser, liquid refrigerant travels to the evaporator, located inside the passenger compartment, where it is allowed to expand, removing heat and cooling the evaporator. The fan directs air over the evaporator, then out the air vents in your car.
Because the working fluid gets both very hot and very cold, it is important to keep moisture out of the system, as ice forming in the compressor can damage it.


As always, neither Instructables nor myself are responsible for any damage you may cause to yourself, your vehicle, or others.

Step 1: What You Will Need and What You Should Know

First, was your car made before 1994? If so, your car likely uses R-12, and this guide isn't for you. However, if you search the engine bay and find a sticker stating that the system has been converted for use with r-134a, continue.

WHAT YOU'LL NEED:
 - Two 12oz. cans of r-134a refrigerant ($9.99/ea)
 - One refrigerant dispenser ($16.00)
 - One pair of goggles

PURCHASING GUIDE:
Refrigerant:
      Purchase the plain r-134a refrigerant from the bottom shelf. Don't be fooled by the shiny cans that have leak sealants and  performance enhancers. These are just "snake oil" and can actually harm your A/C system.

Refrigerant dispenser:
     Your dispenser needs to have both a pressure gauge and a trigger. These are not optional, and are required to do this safely and correctly. DO NOT purchase the dispenser/refrigerant combos.

Note: I do not endorse idQ, EZChill, or SpeedSteed  in any way. These are the parts that I happened to choose, and I am sure their competitor's products are just as good.

Comments

[zipperboy]

I see the car is Toyota. I have recharged my Toyota 2 times. The gauge on the second fill kit was averaged for most North American built cars. I got some pressure info off the Net for my car. Turned out I had to over charge my system according to the gauge in order to have the pressure needed for ice cold air. It does take some time too get there too. Also do not forget to roll back the puncture pin. At first this last time I had not turned it out enough after puncturing the can to get the pressure i needed. Cheers, Phil

[tfellad]

Please be careful refilling freon. I put too much in my system and it shut itself down. Once removed the system resumed properly. Jet be careful

[Redstormx1]

Note this is for some countrys only .

This is no way is legal in Australia , you can buy cans like that . Gas also cost 200 dollars per kilo here.

134a is in 90% of fridges . but you need a different connection sometimes you cant even access the system . you also have a real high chance of over charging or getting the wrong charge in it.
I suggest no one attempts DIY fridge repairs.

[autoed]

Great how to, As an Automotive Tech I need to make clear a few additional items. I really appreciate the note about not using sealers and snake oil. The author is correct that it will create more damage than good. Additionally with modern reclaiming and recycling equipment the repair shop my turn you down once they run the refrigerant id machine on the system. As refrigeration equipment is expensive we (they) do not want sealant or the like inside the reclaiming/recycling tanks. Also modern refrigeration systems hold small amounts of refrigerant compared to old R-12 systems from yester-year. For example a late model Honda civic may hold only 14oz. which is less than a pound. A 1973 chevy impala may have held 4.5 pounds of refrigerant. There are a/c systems that hold only 9 oz. so it would be very easy to overcharge they system. Late model cars are equiped with many sensors and pressure switchs that can shut off your compressor and prevent compressor engagement. I can not tell you how many overcharged systems I have serviced that had electrical problems or the electric cooling fan(s) not working. Please make sure one does a complete inspection prior to adding refrigerant to avoid costly repairs.

[sypher]

COOL instructable... I am also happy to see no one has attacked this as far as evil refrigerant use. So this is the same stuff that is used in modern refrigerators as well, yes?

[cwmaurer]

The freon/refrigerant you add at the fill port goes down that hose directly into the compressor. The refrigerant is in a gaseous state inside this line. If you turn the can upside down, it will dispense liquid refrigerant instead of gaseous. Since liquid is incompressible, it will break the compressor when it hits it.

When the can is empty, no liquid will come out when you turn it upside down, or it will vaporize very quickly inside the line. The reason for turning it upside down is to drain out any additives or oil that may be in the can to lubricate your A/C system that did not vaporize.

[bobluckey]

Great 'ible! I am so doing this. Under filling the system you are very adamant about not turning the can upside down, but its the first step under changing the can. Can explain why it is not to safe (assuming based on CAPS) to turn the can upside, but OK to do so when the can is empty? Is this a precaution to avoid 'Simon Phoenix'ing' oneself or does it affect the pressure going into the system?