T-BERRY'S AUTO REPAIR

  I would like to talk about A/C conversions for now, some of you are probably going to get you're a/c fixed since it's tax refund "I WISH" time and have been told that you need to have your car "retrofitted". I am going to tell you about my experience with it down here in TEXAS since we get all the weather extremes all year round.

 

R-12 is what came in most cars up to '92 & '93. From '93 and on the factories changed over to R-134A, which so far has been working pretty well. In general, If your car came with R-12 and you didn't have a major component failure, (for example: compressor) recharge it with R-12, If their not charging more than $50.00-75.00/lb. If your car came with R-134A the same goes true here also, except for the price, it averages between $10-$25 a pound. When you have a compressor failure in a older model car, you have 3 options:

Repair the existing system = $300.00 to $700.00 (approx.)

Convert it to R-134A = $300.00 to $900.00 (approx.)

Convert it to FREEZE-12 = $200.00 to $500.00 (approx.)

In most cases it's best to go ahead and convert your vehicle to the newer refrigerants because of unpredictable price and availability of R-12. If you have a later Model front wheel or rear wheel drive car, switching to R-134A is your best bet because of warranty policies through various automotive suppliers. You have to change over more parts in some instances, depending on the make of your vehicle, but you will have less trouble in the future if you need to have it serviced again. If price is an issue, and it is available in your area, then I suggest going with FREEZE-12. It is compatible with most A/C systems, you don't have to change all of the o-rings and hoses, it sells for around the same price as R-134A and most of the time you only have to get the system thoroughly flushed and add new oil.

The problems I've seen with R-134A conversions are if the condenser in your car or truck is to small or you don't have enough airflow going across it, it will never get as cold as it used to be, because of the higher temperatures associated with using this Freon. I've only seen this on compact imports and 1 or 2 base model domestic cars. The only thing that could be done was to refill it with R-12 or switch to FREEZE-12.

FREEZE-12 is not without it's problems either, most vehicles will take the change over Without any problems and then there are some that will give you 9 kinds of hell. Most of the problem cars are due to components going out, bad rebuilds or improper service. I have a word to the wise "If the compressor ain't compressing, it ain't gonna matter what Freon you put in it"

I want to state an important fact; Air Conditioning and Cooling Systems are ENTIRELY dependent on temperature difference. If your car is running hotter than usual, then you're a/c is not going to work as well as it should. If the heat index is really high, your car is going to run warmer than usual which in turn is going to make the a/c not work as well as it should. Basically if the outside air temperature flowing across your radiator and condenser is anywhere close to the temperature of the Freon and coolant in your vehicle their not going to perform as well as normal.

WARNING!

THERE ARE A LOT OF OTHER SUBSTITUTES OUT THERE THAT CONTAIN "BUTANE", "PROPANE" IF YOU "TOP OFF" YOUR SYSTEM WITH THESE BLENDS "JUST TILL I MAKE SOME EXTRA MONEY"WHEN YOU HAVE LEAKS, THIS WOULD BE A GOOD TIME TO STOP SMOKING (IF YOU KNOW WHAT I MEAN?)  

Below you will find some tables for label colors and fittings for various refrigerants if it was retrofitted correctly:

 

 I have pictured below a typical Air conditioning schematics to give you a general idea of how it works, of course there are hundreds of different systems out there, but you get the idea.

Recharging Your Car's Air Conditioner with Refrigerant

When servicing automotive air-conditioning systems, vehicle owners generally have several options to recharge a/c systems with refrigerant. One option is to top-off your car's system with refrigerant, and another is to evacuate and recharge the system. Both of these options will provide cool air in the passenger compartment for some period of time. Neither service, however, involves permanently fixing the a/c system leaks that allowed refrigerant to escape resulting in a lack of cool air. You might therefore also choose to have any leaking components in your a/c system repaired or replaced.

By stopping the leak, you will prevent refrigerant from leaking into the atmosphere. The refrigerant in older vehicles is CFC-12 (also known as Freon, a brand name), which is no longer manufactured in the United States because it depletes the ozone layer. As nationwide supplies dwindle, it is becoming increasingly expensive to purchase CFC-12, so that fixing a leak may be more economical in the long run than continuing to purchase CFC-12. This document will provide answers to certain questions you might have about recharging your car with refrigerant during the course of a/c servicing.

1.      What's the difference between a "top-off" and an "evacuation and recharge"? Why would I want one service or the other?

 

2.      I came into the shop with some refrigerant in my car, so why is my technician charging me for the full amount of refrigerant charge -- shouldn't I get credit for the amount I came in with?

 

3.      My technician told me that EPA regulations prohibit topping-off the refrigerant in my car without getting the leak fixed first. Is this true?

 

4.      My technician told me he could not locate the leak in my system, so he topped-off the refrigerant in my car, but did not perform any leak repair. Now it seems to be low on refrigerant again -- I know the leak is still there. What can I do?

1. What's the difference between a "top-off" and an "evacuation and recharge"? Why would I want one service or the other?

A top-off involves simply charging refrigerant into your vehicle. An evacuation and recharge service includes removing whatever remaining refrigerant is in your vehicle, removing impurities from that refrigerant using recycling equipment, recharging it into the vehicle, and adding new refrigerant to replace whatever has leaked out. The cost of both the top-off and the evacuation and recharge will usually include a performance check, and may include a test to discover the source of your leak.

Topping-off alone is less expensive than the evacuation and recharge service. So why would you consider the more expensive evacuation and recharge? The manufacturer of your vehicle has determined that a specific amount of refrigerant -- 2.2 pounds, for example -- is correct for your car. When you bring your vehicle into a service facility, your technician has no way of determining precisely how much refrigerant is left in your vehicle's system. As he tops off the system, then, he relies on his experience to guess how much refrigerant to charge into the system; however, he may undercharge or overcharge the system, thereby affecting system performance. Most recent models have a feature that shuts an overcharged a/c system down in hot weather.

On the other hand, during an evacuation and recharge, once the technician has extracted all remaining refrigerant from the system, he will then be able to charge the system with the precise amount of refrigerant recommended by the vehicle's manufacturer.

Some technicians may tell you that evacuation and recharge is better for the system than a mere top-off because, after the refrigerant is evacuated, it gets cleaned in the recycling equipment, and it's a good idea to clean the refrigerant in your system. There is, in fact, no reason to clean the refrigerant in your system unless you open up the system. If you request that your technician repair or replace system components in order to fix leaks in your system, then he will need to open the system and should recycle the refrigerant.

2. I came into the shop with some refrigerant in my car, so why is my technician charging me for the full amount of refrigerant charge -- shouldn't I get credit for the amount I came in with?

Your service technician has no way of determining precisely how much refrigerant is left in your vehicle's system, so it will be extremely difficult for him to determine how much credit to give you. As a result, many shops charge a flat fee for the service, whether it's a top-off or an evacuation and recharge. Other shops may charge a fee for the labor, and a separate, flat fee for a set amount -- perhaps two pounds -- of refrigerant, whether they've actually charged 1.8 or 2.2 pounds into the vehicle.

EPA requires that shops use special equipment to recover and recycle refrigerant. Some shops pass that cost through to their customers by charging a recycling fee; others choose not to charge a separate fee, but instead to keep whatever refrigerant they recover, in order to make up for the cost of the recycling equipment.

In order to find the source of a leak, the technician will need to add refrigerant to the system if only a small amount of refrigerant remains, and the refrigerant is at a pressure of less than 50 pounds per square inch. However, if there are at least a few ounces of refrigerant already in the system, a technician should not need to add refrigerant in order to identify which components will require replacement. (Keep in mind that a greater quantity of refrigerant -- usually a minimum of 1-1.5 pounds -- must be in the system in order to determine if the system will provide cooling.)

Once the technician has provided his diagnosis and estimate of repair costs to the customer, the customer may decide not to have the repairs performed. The technician should then either remove all the refrigerant that was installed in order to perform the diagnosis, or, if the customer prefers, the technician can top-off the system.

Technicians may occasionally tell their customers that any refrigerant that was in the vehicle when it came into the shop cannot be returned to the customer due to federal regulations. No such federal regulation exists, however.

Even though you are entitled to the refrigerant that was in your vehicle when you brought it in, you should keep in mind that technicians are unable to determine precisely how much refrigerant they have removed from a/c systems -- their recovery equipment does not indicate the amount extracted. So if your technician attempts to remove any refrigerant he added to your system in order to perform a diagnosis, he can only rely on his experience to make an educated guess as to when to turn off his recovery equipment.

3. My technician told me that EPA regulations prohibit topping-off the refrigerant in my car without getting the leak fixed first. Is this true?

EPA regulations do not dictate any particular service, as long as your technician is certified to work with refrigerant and any recycling equipment he uses meets EPA standards. EPA does not require that leak repair be performed before refrigerant is charged into a vehicle, although certain states and localities may require leak repair.

In addition, EPA does not require that the refrigerant be evacuated and cleaned prior to recharging the system with refrigerant. In other words, if your technician tells you that EPA requires evacuation and recharge and does not permit top-off, he is mistaken. If you are unsure about any EPA regulations governing auto air-conditioning, call the Hotline at 800-296-1996.

4. My technician told me he could not locate the leak in my system, so he topped-off the refrigerant in my car, but did not perform any leak repair. Now it seems to be low on refrigerant again -- I know the leak is still there. What can I do?

Leaks can be identified most, but not all, of the time. Your technician may have difficulty locating very small leaks in your a/c system, even if he is very careful and uses the most sophisticated equipment available.

Keep in mind that even when pinhole leaks cause slow emissions over long periods of time, your system may seem to lose its cooling capacity suddenly. This is because most motor vehicle a/c systems have controls that shut off a system when the system pressure drops below a certain point.

In order to maximize the chances that your technician can locate the leak, make sure he uses an electronic leak detector certified under the Society of Automotive Engineers (SAE) J1627 standard. Note that the system does not need to contain a full charge of refrigerant to locate the leak -- a few ounces of refrigerant (about 10% of the normal charge) is sufficient to perform the leak check. Some technicians may also use a trace dye and a black light to help find persistent leaks.

For more information go to EPA HOME PAGE MVAC

Here is a couple of files to download, they can be read with adobe reader:

A/C CAPACITIES CHARTS

GM A/C CONTROLLER REPAIR

 

When do I change my oil

Freon changeover

Why did I fail my emission test

Wiring Diagrams 

TSB's and Recalls

OBD II CODES

NOx FAILURES

Timing Belts_ 1970-1997 Domestic & Imported Cars

Brake Squeals

Glossary

Just For Laughs

Oxygen Sensors

HOME

Please feel free to contact me at the following address:

 E-mail: stberry@netzero.com

 

Last Updated on 01/21/2009
by Scott Throneberry
Email
:stberry@netzero.com