Restore Your Mopar's A/C System, Part I

Now that the cruising season is just about over for most of us, maintenance and rebuild season is just beginning. Because cruising is usually limited to late Spring through early Fall, we don’t want to lose valuable driving time having our cars down for non-essential repairs. For instance, if the heater is broken and it’s August, there’s no reason to rip apart the car to fix it immediately. If we can get by without it, why park the Dodge while the weather is still nice?

One item that didn’t seem to be essential when we were younger is air conditioning. I remember very distinctly removing the factory A/C system from my first car in an attempt to lighten the front end and pick up a few extra horsepower. A futile effort in a 4,000 pound car, but logic doesn’t always come into play when you’re 16. At the time, it seemed to make even more sense because there was a problem with the system, and I didn’t have the money to fix it.

Now that many of us are driving our cars a lot more than the occasional Sunday evening drive, having cold air conditioning is becoming less of a luxury and more of a necessity when it comes to enjoying our time behind the wheel. So now that Fall is here, maybe it’s time to give the A/C system a thorough going through and get it working again.

R-12 or R-134a?
When our Mopars rolled out of the factory’s doors, their A/C systems were charged with Refrigerant 12—Freon. Unfortunately, freon is a chlouroflourocarbon (CFC), and CFCs have since been determined by the scientific community to be a contributor to the depletion of the ozone layer. There has been a lot of debate among different political camps as to whether or not CFCs actually contribute to the depletion, whether or not the hole in the ozone is a naturally occurring event, and even whether or not the hole actually exists, but that debate isn’t for these pages. The only fact we need to concern ourselves with is that R-12 is no longer manufactured in this country, and that the government has mandated that R-12 be replaced with R-134a. That’s the law, and it isn’t going to change.

However, if your R-12 system still performs well, R-12 will be legal and available until the year 2030. That’s the good news. Unfortunately, right now you can expect to pay around $40 per pound for R-12, as opposed to about $8 per pound for R-134a. And domestic production of R-12 only ceased in 1994—think what future prices will be!

When R-134a was first introduced, there was a lot of complaining that it wasn’t as efficient at cooling as R-12. There were concerns that it would hurt systems that were designed for R-12. What that panic and concern boiled down to was that people don’t like change and they don’t like the government telling them they have to change. Since the introduction of R-134a, all the differences have been worked out between R-12 and R-134a, so that an R-134a system is as efficient, and will blow air as cold (or within two to three degrees at the dash vents) as an R-12 system. As for component failure, since the introduction of R-134a, the hoses and mechanicals in well-maintained A/C systems have not been shown to suffer failures as a result of using R-134a in place of R-12.

Notice we said well-maintained—if an R-12 system already has a problem, R-134a isn’t going to hasten it’s demise, but it isn’t going to help, either. Because of this, often when a recently-converted system fails, blame is unfairly placed on the new refrigerant when, in reality, the system probably had never been serviced in its life. Also, and this is important, the filter/drier on your system should be considered a service replacement item, just like any other filter on your car. It should be replaced to rid your system of impurities and debris which it has trapped, whether or not you are converting. If you are converting, the drier needs to be replaced because the desiccant in original R-12 units is not compatible with R-134a—the desiccant pellets will turn to mush and plug the filter, which will damage other components in the system. There are desiccants that are compatible with either coolant, as well as R-134a-specific desiccants.