How do you recharge the air conditioner on a 93 Honda civic?

Answer 1

Not an easy answer, though you would think it should be.

First, Honda was switching over from R-12 to R-134A between 1991 and 1994. Check under the hood for a sticker that identifies which system you have. R-12 is very expensive, if you can even find it any more. It has been phased out and I doubt you can get it. Auto parts stores sell conversion kits, and there is 134A that can be put directly into R-12 systems. Because of this I will use R-134A specs. If you determine that you need 134A, check at the parts store for a kit.

BUT... before you do that, read on... A/C systems are sealed, meaning that the freon doesn't just disappear over time. If your system is out of freon, you have a leak somewhere. Recharging a leaky system won't last as the freon will just leak out again. If the leak is being caused by a bad seal or o-ring, the leaking freon will cause the leak to get steadily worse. A/C system leaks create additional problems beyond a hot ride. When the system is open to the outside air (leaking), air and moisture gets into the system. This moisture can make its way to the evaporator case (thing inside the dash that makes the hot air cold for you), and when it does, the water will freeze inside the evaporator case. This can causes blockage (minor). It can also cause the A/C lubricating oil to sludge up as the oil thickens. If there is enough moisture in the system, the water can cause the evaporator coils to crack, forcing you to pay a lot to get it replaced. Leaks also allow dust and dirt to get into the system (if the leak is bad enough). This gunk can wreak havoc on the A/C compressor. The system has a filter known as a "receiver/dryer". This filter is responsible for keeping moisture and grit out of the system, but it has a limited ability to do so. When servicing an A/C system, it is always recommended that you change the receiver/dryer. *whew* With all that said, lets get to the procedures.

The back yard mechanic answer for how to recharge your A/C system is as follows: 1. Go to a parts store and purchase an R-134A kit that includes 1 can of freon with leak stop and a charging hose 2. Read the instructions on the package. They will state something like, "locate and unscrew the low pressure access port cap; attach adapter hose to low side port; start and run vehicle at idle with A/C on; connect other end of hose to freon; turn can upside down and wait approx. 2 minutes for can to discharge into system; additional cans of freon may be required depending upon your A/C system's capacity." 3. Perform A/C charging and drive off confident that you have saved yourself about $30 in costs over having a garage charge the system for you. If you live way up north and only need the A/C for a very short period throughout the year (say, only between mid June through the first part of August), this may work for you. You've got a '93 Civic, so the car is up in years. A full-blown A/C repair may be more than what your car is worth. In a pinch, or to pinch pennies, the back yard mechanic fix may do just fine for you.

If you plan to drive the car long distances, or will need to A/C for more than an occasional grocery run here is the proper way to charge an A/C system: 1. You need to repair the leak... which means you need to FIND the leak (unless you already known where it is). To find the A/C leak, go to the auto parts store and buy a can of freon charge that contains leak detector dye. Follow the instructions on the package (it should contain the necessary hoses) and run the A/C system after you put the freon in. The dye is made to be visible under a black light and will highlight the area of the A/C leak like a neon sign. Once you find the leak, make the repair. Make sure you replace the receiver/dryer, too. 2. Now that the leaks are fixed and the system (should be) air tight, you need to draw the system down into a vacuum. This does two things. First, it is a test to ensure the system is, in fact, properly sealed. Second, it removes air and boils out any moisture in the system (which there will be since the system was opened to the outside air). As stated above, air and moisture are the bane of A/C systems and can spell the end of your A/C system, and of your wallet, in a hurry. Why does drawing the system down to a vacuum boil out the water (instead of sucking it out)? Water's boiling temperature (the point where it turns into a gas) varies depending on air pressure. Water boils faster on Mt. Everest than it does in Death Valley. This is why packaged foods list different cooking times depending on your elevation. To help keep water in the radiator from boiling, the engine cooling system is pressurized (radiator cap). In a vacuum, water will begin to boil at room temperature or lower, depending on the degree of vacuum. As the water boils, it turns into a vapor and is pulled out by the vacuum pump. To draw the system down into a vacuum you will need a special vacuum pump with a line hooked up to the low-side access port. The system should be drawn down to around 10 and it should stay there for about 15 minutes. This process may take 60 minutes or more. Some service shops recommend evacuating the system for a minimum of 45 minutes, just to ensure the system is completely clean. Once it has been at 10 PSI of vacuum for 15 minutes, shut the vacuum pump off and watch the vacuum gauge to ensure to does not return back to zero (indicating a leak in the system). If it doesn't hold, you'll have to find the leak, fix it, and repeat the process. 3. Now that the system is free of leaks and is in a state of vacuum, it's time to recharge it. You should have already found the A/C ports on your system. If memory serves well, the access ports are located in close proximity to each other on the driver's side of the car, under the hood, near the radiator. You should see two black screw-on caps attached to aluminum pipes. One of the caps will be larger than the other, and it will be on the larger of the two pipes. This larger cap/pipe is your low-pressure line. The smaller cap is the high-pressure side. The capacity of A/C systems varies depending on how the system was made. I believe your system holds around 1.4 lbs of freon (roughly one and a half to two cans). Purchase your freon and the hoses necessary to charge the system if you don't already have them. Make sure the freon has refrigerant oil mixed in with it! The charging hose assembly should have 3 hoses: a blue one, a yellow one, and a red one. The blue hose is your low-pressure hose. It will hook to the low pressure port on your system. The red hose is for your high-pressure side. The yellow hose is where you will hook the cans of freon into the system. The ports are different sizes and the hoses will match them. To charge the system, connect the low and high pressure hoses to the correct ports on the A/C system. Next, start the car and run at idle with the A/C system on Max A/C, and the air pulling from the outside (not recirculate). Connect one can of freon to the yellow line and turn the can upside down - this is so the liquid freon is pulled into the system instead of the gaseous freon that can build up in the can. Watch the pressure gauges on the charging hose set-up. Continue adding freon until the system is fully charged. The pressures are what will indicate to you when the system is fully charged.

A/C system pressures:

The following info should help you determine when your system is fully charged. These are only basic guidelines. The pressures will vary greatly depending on what temperature it is outside and the relative humidity. The A/C system relies on the condensor (radiator-like thing in the front of the actual radiator) to turn the freon from a gas back into a liquid. If it's hot outside, the heat exchange will be much different than if it is 70 degrees, so the pressure in the A/C system will change accordingly. Likewise, if it is humid out, the condensor won't work as efficiently. Low side - 0-20 PSI - System is low and requires more freon.

20-45 PSI - System is fully charged.

45-60 PSI - System may have too much freon in it. Stop adding freon.

Over 60 PSI - This pressure is too high and may indicate either too much freon or other problems. Get the system checked out and repaired if necessary. High side - 0-150 PSI - System is low and requires more freon.

150-250 PSI - System is fully charged.

250-325 PSI - System may have too much freon in it. Stop adding freon.

Over 325 PSI - This pressure is too high and may indicate either too much freon or other problems. Get the system checked out and repaired if necessary.

My recommendations -

The A/C system can be pretty expensive to repair properly. Most people who want to save money and fix it themselves usually find themselves in one of two positions - 1. The system never works properly so they opt for 55-down A/C (driving 55 mph with the window down) 2. They find themselves in a cycle of constantly recharging the system and wind up spending more money in freon and eventual parts replacement than they would have had they just fixed it right the first time.

Unless you are fairly experienced (and have access to the right equipment) or are viewing the A/C system as a convenience rather than as a necessity, take the car to a shop and have it fixed properly. If they are telling you that the cost to fix the system is way more than you can budget for, you can repair the components of the system yourself fairly easily (swapping out A/C lines, a compressor, receiver/dryer, etc.) and should only have to use the shop to evacuate and recharge the system (about $40 to $70 bucks).

Common misconceptions -

1. More freon means colder A/C The A/C system runs on a delicate balance between freon and space. The system needs to have enough freon to be able to be effective, but too much freon keeps it from evaproating and absorbing heat form the air. If the system seems to be running cold, but not cold enough, don't just assume that you can add a can of freon and that will fix the problem. It may (if the system is low), but it may also cause more problems and actually reduce the system's ability to cool.

2. Just fill it with freon and go. Evacuating isn't necessary and is just a way for garages to make money. As stated before, drawing the system down into a vacuum removes water (and air) from the system. This is critical to the proper functioning and life of the A/C system. Water freezes, corrodes, causes blockages, and can impede the system's lubrication. The air contains impurities that can cause problems. It can also cause increased system pressure and can reduce the system's ability to cool properly. Have the system fixed properly and get it evacuated before charging it with freon.

3. Put stop-leak in to fix the system and to prevent it from leaking again. A/C system stop leak is just like any other vehicle additive. It can work (depending on what is wrong), but is not the right thing to do unless you absolutely cannot afford to fix the problem and need to put a band-aid on it temporarily. I know folks who have used it to "get them over the hump", or to keep their system going through the hot months each year because they don't want to (or can't afford to) spend the money to fix the system. If that's what one needs to do, okay. However, I do not recommend adding stop leak as a preventative measure.