Repair And Fix it

The typical automotive air-conditioning system uses a compressor, receiver drier, condenser, rigerant, evaporator and thermostatic valve. This was not so in the early days of automotive air conditioning for cars and trucks, which were primitive by todays standards. The history of air conditioning started with a patent submitted by Willis Carrier in 1906, for building structures. The invention caught on with car and truck applications during the early middle half of the 20th century.

Automotive Air Conditioning Debut

A New York company was the first source of air conditioners used on cars in 1933. The units were highly customized and individually fitted on expensive, privately owned cars and limousines.

Freon Beginnings

The compound chemical Freon, invented by Charles Kettering and Thomas Midgley, was composed of chlorofluorocarbons -- a mixture of carbon, fluorine and halogens of hydrogen and chlorine. Although the invention and application of Freon was first used in air-conditioned buildings, it would later be applied to automotive air-conditioning systems that used coils, condensers and compressors to circulate a rigerant.

Packard Motors

The Packard Motor Car Company offered the first workable air conditioner and heater combination for cars in 1939. The unit cost $274, considered an expensive option at the time. The compressor, a 1.5-ton unit, ran off a belt from the engine. The unit had no thermostat control for turning it down or shutting it off, as it required removal of the belt from the engine. The cool air was gathered at the rear of the vehicle and discharged forward.

Cadillac

Cadillac followed suit in 1941, manufacturing its own air-conditioning system, similar to the Packard design. Cadillac sold over 400 cars that had the expensive option. The bulky unit was located behind the rear passenger seat; it also had to be deactivated by removing the compressor belt.

Frederick McKinley Jones

Frederick Jones was a mechanic and inventor who applied for and received more than 40 rigeration patents for air conditioning. In July 1940, he was issued a patent for a cooling device that mounted to the roof of a truck. Not long after, the invention was produced for rigerated trucks that transported flash-frozen foods, which was an invention of Clarence Birdseye.

Nash

The Nash-Kelvinator Corporation was the first manufacturer of a integrated ventilating, heating and air-conditioning system. The unit was mass produced and used on the Nash Ambassador in 1954. It boasted a compact style, affordable price at $345, adjustable dash controls, electric clutch, dash-mounted vents and was located entirely in the engine bay. The mass produced units were called the "All-Weather Eye."

General Motors

General Motors manufactured a front engine-mounted air conditioning system in 1954. It came as an option on its Pontiac cars, which had straight eight-cylinder engines. Separate controls were added for air distribution and cooling levels. The design differed slightly from the Nash layout and concept.

The 1960s

Air conditioning for cars and trucks picked up in popularity and application by 1960, outfitting about 20 percent of U.S. vehicles. The Southwest used systems in 80 percent of its vehicles. American Motors introduced air conditioning on all AMC Ambassador models starting in 1968. At the turn of 1969, 54 percent of all domestic vehicles had air-conditioning systems. Automatic climate control thermostats were first introduced and applied during this time.

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Introduction of R-134a

R-134a rigerant was introduced in 1992 as a replacement for the original R-12 Freon. The old R-12 Freon, invented by Kettering and Midgley, was found to contain ozone-destroying chlorofluorocarbons. The new R-134a had no toxic or ozone depleting chemicals, and followed the criteria set forth by the Environmental Protection Agency. All new vehicles manufactured after 1995 were fitted with new air-conditioning systems that used only R-134a rigerant. R-12 was discontinued, with some countries outlawing its use. As of 2011, 99 percent of all vehicles manufactured and on the road have air-conditioning systems, with climate control programming, directional vents and increased performance, allowing for better fuel economy.

If your air conditioning malfunctions in your 1999 Lexus LS400, prompt servicing is the best way to protect your Lexus investment. Any automotive mechanic can recharge your air conditioner, but damage to your air conditioning system requires Lexus service technicians, certified by the Lexus Commitment to Excellence program, if you want your warranty to stand. Mechanical or electrical air conditioning problems may mean replacing the entire system, the compressor, condenser, accumulator, evaporator, blower motor, control unit, fan and clutch.

Compressor Specifications

The Lexus Part Store sells new and urbished used air conditioner compressors for the 1999 Lexus LS400. The remanufactured compressors come with a core charge. The LS400 compressor has six grooves, a 1.65-inch line, a mount manifold, a tangent mount, a 4.5-inch pulley, a speed sensor switch and a clutch. The urbished compressor carries a two-year or 24,000-mile warranty. The new compressor cost $442 in 2010 and is under warranty for one year. The urbished compressor cost $395 in 2010. A core charge of $61 in 2010 was imposed on top of the part cost; the core charge is unded to the purchaser upon receipt of the old compressor.

Condenser Function

The condenser collects filth and oil from the compressor. Refrigerant may carry this filth through the condenser to the expansion valve, clogging the valve or tube. If oil cannot flow through the condenser, the compressor cannot receive oil, and the compressor will lack lubrication. If the condenser is dirty, it may be necessary to replace it. Flushing the compressor definitely moves sludge through the system. The sludge may form a blockage or damage the compressor. If you damage your air conditioner by flushing it, your warranty will be void, at least for the air conditioner.

Condenser Specifications

The Lexus Parts Store website lists two condensers for a 1999 Lexus LS400. A new first-class condenser with a clutch, manufactured from high-quality materials for extended reliability, cost $235 in 2010. A limited 1-year warranty covers manufacturers defects in the compressor. A second aluminum parallel flow condenser cost $139 in 2010. It is guaranteed to fit without leaking. Both condensers reduce noise and vibration. A chrome-plated compressor gasket or trim ring fits most cars and trucks with 7-inch radial compressors. The gasket costs $29 from the Lexus Parts Store in 2010 and comes with a 90-day warranty.

Automotive air conditioning is considered a necessity for most people. Consequently, we have come a long way in revolutionizing the air conditioners in our cars. The latest upgrades to this useful invention include the ability to set a desired temperature and have the system adjust automatically. Automotive air conditioners may be of two types. The main difference between the two types lies in the device that lowers the refrigerant pressure. Each has advantages and disadvantages.

Components

The main shared components of the two types of car air conditioning include the compressor, condenser, evaporator, orifice tube, thermal expansion valve, receiver-drier and accumulator. The orifice tube may be replaced by a thermal expansion valve, thus the two types of automotive air conditioning.

Process

The compressor pulls low-pressure refrigerant from the evaporator and compresses it into high-pressure refrigerant vapor that is moved to the condenser. During this process, the temperature of the refrigerant is increased. While the high-pressure refrigerant is in the condenser, it is cooled down by fans blowing across the condenser fins. The refrigerant is then collected by the receiver-drier, which is filtered and dried.

As a result of this process, liquid refrigerant builds up at the bottom of the receiver-drier, with the vapor at the top. The expansion valve then allows a certain amount of the liquid refrigerant to enter the evaporator. During its final stage, the refrigerant leaves the evaporator as a gas by absorbing the heat inside the car. As the warm air from inside the automobile is forced onto the evaporator fins, it is cooled by the refrigerant and released back to the cars interior. The moisture from the warm air after the cooling process is drained away.

Orifice Tube System

The orifice tube systems are commonly found in General Motors (GM) and Ford models. The orifice tube is located in the inlet tube of the evaporator or in the liquid line. The orifice tube is no longer than 3 inches. It is made up of small brass tubes surrounded by plastic, covered with a filter at each end.

Disadvantages of the orifice tube system include clogging caused by debris and high costs of repairing or replacing the tube. To avoid the clogging of debris in the orifice tube system, install a larger pre-filter in front of the orifice tube.

Expansion Valve System

The expansion valve system is generally used on after-market systems. This system is efficient at regulating refrigerant to the evaporator. It is located at the firewall, between the evaporator inlet and outlet tubes and the liquid and section lines. It may clog with debris. Additionally, the valve contains small moving parts that may stick together or malfunction because of corrosion.