TRB on Tue February 24, 2004 1:22 PM
HOW REPAIR KITS BRING YOUR
A/C SYSTEM BACK FROM
face=arial color=white>The side-by-side comparison of a new orifice
tube with one that has been clogged by metal particles from a
failed compressor demonstrates how contamination is spread throughout
an A/C system. What
is "Black Death"?
"Black Death," as it is known by A/C system service professionals,
results from a catastrophic breakdown of the refrigerant-lubricant
which in turn causes excessive wear inside the compressor. In a
typical case of "Black Death," metal particles are circulated throughout
the system contaminating other components and necessitating either
thorough flushing or complete replacement. The swash-plate compressors
used by Ford are particularly susceptible to this problem. Similar
damage can also occur inside the compressors used in some GM and
Chrysler A/C systems. Some wear is normal.
During normal operation, a small amount of wear occurs inside
the compressor due to the contact of moving metal parts. Much
like the oil used to lubricate an engine, the combined refrigerant-lubricant
used in an A/C system minimizes wear. However, the amount of wear
and the size of the particles generated can increase significantly
when the compressor is operated on a low charge of the PAG (Poly
Alkalyne Glycol) oil or mineral oil recommended for specific A/C
systems. Loose particles contaminate
When an A/C system is operated under low-charge conditions, loose
wear particles, often quite large and potentially damaging, are
circulated throughout the system. They lodge in various system
components and frequently impede or even block the flow of the
refrigerant-lubricant. If only a new compressor is installed into
a system that has not been thoroughly flushed, there is a good
possibility that the new compressor will fail again, thereby voiding
the warranty and resulting in another expensive repair.
Recognizing the problem.
Your A/C system professional who uses Arizona Mobile Air Quality Parts knows the usual signs of compressor failure and can diagnose the presence of "Black Death" in several ways:
Your compressor may be functional, but extremely noisy during operation.
In turning the compressor clutch, you may feel "hard" spots.
The compressor may be totally frozen or locked up.
Signs of contamination may be present at the orifice tube and/or the inlet and outlet ports when the hose manifold is removed.
Solving the problem.
Depending on the severity of the damage and the extent of the contamination, some "Black Death" problems can be repaired by flushing the A/C system with solvents.
Segments of the system are cleansed individually during the flushing process. This can be very time consuming and expensive but is must for a successful repair.
At the minimum, a new or remanufactured compressor, accumulator/drier and expansion device must be installed following this procedure. Frequently, other components also require
replacement. From a cost and performance viewpoint, many A/C system technicians find that replacement of all contaminated components is the best approach.
Doing The Job Right, The
First Time Working with thousands of A/C system service professionals, Arizona Mobile Air Inc and AirPro Quality Parts were among the first to notice the increase in costly repeat-visit
repairs caused by "Black Death." They typically include a compressor, accumulator, manifold, liquid line, condenser and orifice tube.
In addition: New components are free of any contaminants.
The risk of repeating the problem with particles not removed during the flushing or filtering process is eliminated.
Arizona Mobile Air Inc. auto a/c system parts and components match the original-equipment fit and are easy to install.
In bringing your A/C system back from the ravages of "Black Death," you can be sure the job is done right, the first time.
The A/C system diagram and the individual component photos below. Provide additional information about A/C system flow, component function and the devastating
effects of "Black Death."
Key Components and Functions.
To remove heat from the passenger compartment, all major A/C system components must operate at peak efficiency. Each component is dependent upon the function of the others.
The spread of contaminants reduces system efficiency and will eventually lock up the compressor or block the flow of the refrigerant-lubricant.
-- Responsible for pumping refrigerant through the air conditioning system and increasing the pressure of incoming refrigerant gases. Located under the hood. Belt driven. Problems with inadequate lubrication inside the compressor are the cause of excessive wear, contamination and the spread of particles throughout the A/C system.Manifold
-- Connects the suction and discharge lines to the compressor. Metal particles adhering to the internal walls are evidence of system-wide contamination.Condenser
-- Heat exchanger responsible for changing refrigerant from a high-pressure gas state to a high-pressure liquid state through principles of condensation. Located in front of radiator. The small passages inside the condenser are very susceptible to clogging from the particles that enter under high pressure. Liquid Line
-- Moves the high-pressure liquid through the system. Particles frequently cling to the interior walls and catch other particles as they flow through.Orifice Tube
-- Responsible for regulating refrigerant flow to the evaporator and changing refrigerant pressure from high to low. Located under the hood. The photo top of page
comparing a clogged orifice tube to a new one demonstrates the seriousness of the problem caused by system contamination.Evaporator
-- Responsible for changing state of refrigerant from low-pressure liquid to low-pressure gas through principles of evaporation. Located in the passenger compartment. In all but the most serious instances of system contamination, the evaporator is the one major component that does not need replacement. Any particles that reach the evaporator tend to flow through.Accumulator
-- Responsible for storing excess refrigerant not utilized by evaporator, filtering contaminants out of refrigerant and removing any moisture that is in system. Located under the hood. Due to the concentrations of particles that are trapped here, the accumulator frequently requires replacement.