Installing and Air Conditioning System

Air conditioning is probably at the top of the list when it comes to personal pampering for classic trucks. The benefits of driving in chilly comfort are hard to exaggerate, but all it takes is one long drive on a hot summer day, and you’ll see how nice it is to arrive cool and fresh. Most people think installing an air conditioning system in a classic truck is very complicated and often pass up the opportunity. This is wrong. Way wrong. With the help of a company like Vintage Air, your classic truck can be pumping out ice cubes after a weekend of relatively simple wrench turning.

The Sure Fit series from Vintage Air is designed to bolt in to specific models of trucks (we used a ’64 Chevy pickup for this story) with a minimal amount of fuss. Several universal models are also available, so any vintage truck can have a Vintage Air system. On Sure Fit versions, the drier comes already mounted to the condenser; the condenser has mounting brackets specifically designed for your truck; the hard lines on the condenser are prebent to run the most logical path; the evaporator fits under the dash perfectly with supplied mounts; the compressor is just the right size for the system and…hey, wait a minute—maybe you don’t know what all these parts are and how they work. Let’s take a little time to go over how an air conditioning system works.

Cooling the inside of your classic truck is more accurately a matter of taking the heat out of the air through an endless cycle of evaporation and condensation. When the refrigerant in your system evaporates (changing from a liquid to a gas) it absorbs heat from inside the air itself, and when it condenses it transfers the heat up to the air flowing past the condenser.

REFRIGERANTS

The standard A/C refrigerant until about 1992 was CFC-12, a nasty little chlorofluorocarbon that forms phosgene gas when exposed to hot metal or an open flame. Phosgene gas was used during World War I as nerve gas. Exposure can cause at the least headaches and dizziness. The government started phasing out CFC-12 use in the ’90s, because of concerns about chlorofluorocarbon’s affect on the environment; the replacement refrigerant, HFC-134A, was not exactly welcomed with open arms. Initial reports were that HFC-134A didn’t work as well and, of course, the price took a jump upward. In the past several years, manufacturers have figured out how to make their air-conditioning systems work with the new refrigerant, and now the price of CFC-12 has skyrocketed as availability has tightened. The bottom line is that you are better off sticking with the modern HFC-134A refrigerant. A new A/C system is designed to use HFC-134A, and technicians now know how to fill the system effectively (no more overfilling to get better performance, for example). Vintage Air systems use the modern refrigerant.

CONDENSER

The condenser is actually one of the most important parts of an air-conditioning system. It looks like a small radiator or a transmission cooler located in front of your radiator, and it’s the key to good performance. When it comes to condensers, bigger is better. The more heat you can remove from your refrigerant, the lower the pressure within the system will be. With lower heat and lower pressure there’s less demand on the compressor and less vibration. The condenser should have about 25 percent more capacity than the evaporator you’re using (in a Sure Fit system, that’s already figured out for you).

COMPRESSOR

The compressor pressurizes the refrigerant and moves it through the system. A lot of things happen because of pressure, but we’d need another two pages to explain—so let’s just say that it’s a part of the system you can’t live without. When it comes to selecting a compressor, bigger is not better. Too big can actually be a problem, as it creates excess pressure and heat, works the engine harder, and can lead to mount failure. Appearance is a consideration as well, because most people spend a lot of time making the engine compartment looks as good as possible. A Sanden unit is pretty much the standard and it comes with the Sure Fit package. Alan Grove is just one company that makes brackets to fit a Sanden compressor to any engine.

RECEIVER/DRIER

This part looks like a radiator overflow tank, and most people have no idea what it does. The receiver/drier is located in the system right after the condenser. As you now know, the condenser turns the refrigerant from a gas to a liquid, but it’s not 100 percent. Some gas makes it through without transforming. The receiver/drier separates the liquid refrigerant from the gas and only allows liquid to pass to the evaporator. The receiver/drier filters the refrigerant and also removes moisture. It acts as a surge tank, too. Since an HFC-134A system is less tolerant of moisture, you want a good receiver/drier. You might even want a chrome one to spice up the engine compartment.

EVAPORATOR

This is the unit that fits under (or in) your dash. It has a core, an expansion valve, a blower, and a set of air outlets. The first concern is if it will fit in your truck (a Sure Fit is designed for a specific model so it fits correctly), and the second is if it will cool the truck adequately. Since trucks don’t have a lot of interior space there usually isn’t a need to go with a monster-size unit. One key to look for is the convenience (and appearance) of the controls.