It would probably boggle the mind if we could find out how much has been spent since 1994, when the market was forced to use R134a and its poor lubricating synthetic oils. We estimate it would run into the billions. Somebody has gotten wealthy, and I don't think it is the trucker.

We are eager to blame the trucker for not getting enough sleep and rest between driving times. Try sitting in his seat behind that hot engine and hot highway with no air conditioning because he can't afford to have it repaired (or if he could afford it, he can't find anyone to repair it).

We think the car air condition system is bad, but some truckers are using two and three compressors in a season. This is terrible and totally unnecessary. With the use of HC12a/134+, good oil, and upgrading the condenser fan operation, we are extending greatly the life of our compressors, and the entire air condition system.

All new compressors are well built pumps. With proper oiling and pressures they should last a minimum of 2 years and 100,000 miles or longer.

The three main problems we're having in air conditioning are HIGH PRESSURES, POOR LUBRICATION, AND POOR COOLING. Why are we having these problems? First, R134a is a poor refrigerant to start with, it takes high pressures to cool, and it takes special synthetic oils which do not lubricate very well. Simply changing to HC12a/134+ is a step in the right direction, but not the total solution to the problem. Let's take a look at the way the air condition system was designed. Back in 1994 the manufacturers were forced to use R134a refrigerant. R134a requires the use of PAG or ESTER oil and needs higher pressures to cool. Using HC12a/134+ will allow us to use more oil and lower pressures.

Let's start off by lowering pressure (Hydro Cool supplies a switch kit). Install a switch in the high pressure line to engage the air fan clutch at 250psi and opens at 190psi. Most switches on trucks today close at 350psi and open at 300psi, which creates a lot of heat from the condenser, causing the fan to run even more. Tests run by some fan clutch suppliers claim that trucks use 15-25% more fuel when the fan is running. The low pressures of HC12a/134+ will never need a fan to cool the condenser while traveling on the highway. It will only be needed while traveling in slow traffic or idling. Most trucks also do not have thermal switches to cut off the compressor when the evaporator gets too cold. We supply these switches. Those who keep good fuel records will appreciate these huge savings. This takes care of the pressures and cooling problems.

Now for the poor lubrication. Natural mineral oil is by far the best lubricant in air conditioning, but we must deal with what we already have in our systems. (We do not recommend PAG oil in anything that turns faster than a Mule Wagon wheel.) Most new trucks come from the factory with PAG or ESTER. When adding oil, ESTER is added in both cases. When there is a major problem and the compressor needs changing:

• Change driers/accumulators
• Clean expansion valves/orifice tubes
• Flush system (if contaminated use "Air Repair" flush, if not contaminated flush with shop air

When you have this truck finished you should be running between 25-35psi on the low side and around 200psi on the high side. Your temperature should be less than 40 degrees at the vents on the highway. Remember final charge, with the fan running, and engine set at 1500 RPM.