Air Conditioner
09-20-2005 | 05:53 PM
#1
Air Conditioner I just bought a 98 Z28 off of a friend, and the a/c isn't working, he has the compressor, and one of the other components to the a/c system, i have one more to buy to cover the warranty, but i was wondering if anyone knows of any articles, or can just give me some general info on the a/c system on these vehicles, and how difficult it would be to change, if i should drop the money and just get it done professionally, any advice would be greatly appreciated rossperrt.abbott@navy.mil either email or repost thanks
09-20-2005 | 11:12 PM
#2
TECH Veteran
Joined: Dec 2004
Posts: 4,012
Likes: 1
From: Beaumont, TX
Here's a summary of how to replace the compressor: https://ls1tech.com/forums/showpost....73&postcount=9
Not quite sure what kind of information you're asking for, but here's some of the GM description/operation info for the f-body HVAC
Air Conditioning (A/C) System Description
The HVAC system delivers air that has been heated or cooled and dehumidified for occupant comfort. The HVAC system also provides the following features:
Ventilation
Windshield defrosting
Side window defogging
During most operating condition, the blower motor draws the outside air through the heater and air conditioning module. The forward movement of the vehicle forces additional air into the vehicle. The following actions occur in the evaporator core when the compressor is on:
The air is filtered
The air is dehumidified
The air is cooled to about 2°C (35°F)
Some of the air then passes through the heater core where the flow of hot coolant reheats the air. Depending on the temperature door position, the heated air is mixed with cold air from the evaporator before the air enters into the passenger compartment. The air enters the passenger compartment through the upper, lower, or defroster outlets. This provides positive air flow even if the windows are closed.
When the Recirc mode is selected, most of the air entering the evaporator and heater core module is recirculated from the passenger compartment. Recirculated air is most likely cooler and dryer than outside air in very hot weather.
Air Distribution System Description
Vacuum regulates air flow through the system. Depending on the mode selected, the mode valves mix and direct either cooled, heated, or outside air through the air ducts. The various modes of operation are as follows:
RECIRC AIR This mode limits the amount of fresh air that enters the vehicle by recirculating most of the air inside the vehicle. This setting helps cool the air quickly and helps to limit odors from entering the vehicle. The air is delivered through the IP outlets.
OUTSIDE AIR This mode draws fresh air in from the outside and delivers the air through the IP outlets. This setting is used while defrosting or defogging the windows in order to help clear moisture.
BI/LEVEL This mode draws air from the outside. This mode directs air into the vehicle in two ways:
Cooler air is directed toward the upper body through the IP outlets.
Warmer air is directed through the lower outlets.
UPPER This mode directs most of the air through the IP outlets and a small amount of the air to the lower outlets.
LOWER This mode directs air into the vehicle in several ways:
Most of the air is directed through the lower ducts to the floor area of the vehicle.
Some of the air is directed toward the windshield and the side window vents.
DEFOG This mode directs air in the vehicle in several ways:
Air is divided between the windshield and the lower outlets
A small amount of the air is directed toward the side window vents. This mode is useful when fog appears to the windshield or side glass due to rain or snowy conditions.
DEFROST This mode directs most of the air to the windshield for quick removal of fog or frost from the windshield. A small amount of air is also directed toward the lower and side window outlets.
Refrigeration System Description
VDOT Refrigeration System
(1) Compressor
(2) Condenser
(3) Evaporator
(4) Accumulator
(5) Low Pressure Liquid
(6) Low Pressure Vapor
(7) High Pressure Liquid
(8) High Pressure Vapor
(9) Expansion (Orifice) Tube
(10) Liquid Line
(11) Pressure Relief Valve
The variable displacement orifice tube (VDOT) system is comprised of the following components:
A variable displacement compressor (1)
A fixed expansion tube (5)
This system matches the air conditioning demands under all modes without cycling. The basic compressor mechanism is a variable angle wobble-plate with five cylinders. The five cylinders are oriented around a common axis. The center of control of the compressor displacement is the control valve. The control valve is actuated by a bellows. The control valve is located in the rear head of the compressor (1) that senses compressor suction pressure. the crankcase-suction pressure differential controls the following conditions:
The wobble-plate angle
The compressor displacement
When the A/C capacity demand is high, the suction pressure will be above the control point. The valve performs the following functions:
Maintains a bleed discharge gas into the crankcase
Closes off a passage from the crankcase to the suction plenum
The angle of the wobble-plate is controlled by a force balance on the five pistons. A slight elevation of the crankcase suction pressure differential creates a total force on the pistons. The force on the pistons produces a movement about the wobble-plate pivot pin that reduces the plate angle.
Refrigerant R-134a
Caution: Avoid breathing the A/C Refrigerant 134a (R-134a) and the lubricant vapor or the mist. Exposure may irritate the eyes, nose, and throat. Work in a well ventilated area. In order to remove R-134a from the A/C system, use service equipment that is certified to meet the requirements of SAE J 2210 (R-134a recycling equipment). If an accidental system discharge occurs, ventilate the work area before continuing service. Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.
Refrigerant performs the following functions in the air conditioning system:
Absorbs heat
Carries heat
Releases heat
These vehicles use Refrigerant-134a (R-134a). Refrigerant-134a is a nontoxic, nonflammable, clear, colorless liquefied gas.
Handling Compressor Oil
Use approved compressor oil from a closed, sealed container. When adding refrigerant oil, the transfer device and container should be clean and dry to minimize the possibility of contamination. Refrigerant oil is moisture-free and will readily absorb moisture from the air. Do not open the oil container until the service procedure requires oil. Cap the oil immediately after use. Always store compressor oil in a closed sealed container. Compressor oil left in open or improperly sealed containers will absorb moisture. Do not reuse oil that has been removed from the refrigeration system. Dispose of used oil properly, according to local regulations.
Handling Air Conditioning (A/C) Compressor
Do not strike, drop, or turn the compressor upside down. If the compressor is knocked over or turned upside down, rotate the compressor's clutch 5-6 times by hand to circulate the oil which has settled in the cylinder. Sudden rotation with oil in the cylinder can cause valve damage and adversely affect durability.
Handling of Refrigerant Lines and Fittings
Ensure that the metal lines do not exhibit the following conditions. This will prevent the loss of system capacity due to line restriction:
Dents
Kinks
Do not bend the flexible hose line to a radius of more than 4 times the diameter of the hose.
Do not allow the flexible hose line to come within a distance of 63.5 mm (2 ½ in) of the exhaust manifold.
Inspect the flexible hose lines regularly. Replace the flexible hose line with new hose if one of the following conditions exist:
Leaks
Brittleness
Deterioration
Before disconnecting any fitting in the refrigeration system, discharge all of the Refrigerant-134a.
Once you open a refrigerant line to the atmosphere, cap or tape the line immediately. This will prevent any of the following items from entering the line:
Moisture
Dirt
Use the proper wrenches when you make connections on the O-ring fittings. Back-up the opposing fitting with a wrench in order to prevent distortion of the following areas:
The connecting lines
The components
Tighten all of the tubing connections to the specified torque. Too much or too little torque may result in the following conditions:
Loose joints
Deformed joint parts
Refrigerant leakage
An inoperative A/C system
Ensure that the O-rings and the seats are in perfect condition. A burr or a piece of dirt may cause a refrigerant leak.
Install new O-rings that you have lubricated with the mineral base 525 viscosity refrigerant oil. Do not use polyalkylene glycol (PAG) synthetic oil. Do not wipe the threads with a cloth.
Keep PAG synthetic refrigerant oil off fitting threads. Long term contact of PAG synthetic oil on threads may cause future disassembly difficulties. Flush threads of fitting with mineral base 525 viscosity refrigerant oil. Do not use PAG synthetic oil. Do not wipe threads with a cloth.
Not quite sure what kind of information you're asking for, but here's some of the GM description/operation info for the f-body HVAC
Air Conditioning (A/C) System Description
The HVAC system delivers air that has been heated or cooled and dehumidified for occupant comfort. The HVAC system also provides the following features:
Ventilation
Windshield defrosting
Side window defogging
During most operating condition, the blower motor draws the outside air through the heater and air conditioning module. The forward movement of the vehicle forces additional air into the vehicle. The following actions occur in the evaporator core when the compressor is on:
The air is filtered
The air is dehumidified
The air is cooled to about 2°C (35°F)
Some of the air then passes through the heater core where the flow of hot coolant reheats the air. Depending on the temperature door position, the heated air is mixed with cold air from the evaporator before the air enters into the passenger compartment. The air enters the passenger compartment through the upper, lower, or defroster outlets. This provides positive air flow even if the windows are closed.
When the Recirc mode is selected, most of the air entering the evaporator and heater core module is recirculated from the passenger compartment. Recirculated air is most likely cooler and dryer than outside air in very hot weather.
Air Distribution System Description
Vacuum regulates air flow through the system. Depending on the mode selected, the mode valves mix and direct either cooled, heated, or outside air through the air ducts. The various modes of operation are as follows:
RECIRC AIR This mode limits the amount of fresh air that enters the vehicle by recirculating most of the air inside the vehicle. This setting helps cool the air quickly and helps to limit odors from entering the vehicle. The air is delivered through the IP outlets.
OUTSIDE AIR This mode draws fresh air in from the outside and delivers the air through the IP outlets. This setting is used while defrosting or defogging the windows in order to help clear moisture.
BI/LEVEL This mode draws air from the outside. This mode directs air into the vehicle in two ways:
Cooler air is directed toward the upper body through the IP outlets.
Warmer air is directed through the lower outlets.
UPPER This mode directs most of the air through the IP outlets and a small amount of the air to the lower outlets.
LOWER This mode directs air into the vehicle in several ways:
Most of the air is directed through the lower ducts to the floor area of the vehicle.
Some of the air is directed toward the windshield and the side window vents.
DEFOG This mode directs air in the vehicle in several ways:
Air is divided between the windshield and the lower outlets
A small amount of the air is directed toward the side window vents. This mode is useful when fog appears to the windshield or side glass due to rain or snowy conditions.
DEFROST This mode directs most of the air to the windshield for quick removal of fog or frost from the windshield. A small amount of air is also directed toward the lower and side window outlets.
Refrigeration System Description
VDOT Refrigeration System
(1) Compressor
(2) Condenser
(3) Evaporator
(4) Accumulator
(5) Low Pressure Liquid
(6) Low Pressure Vapor
(7) High Pressure Liquid
(8) High Pressure Vapor
(9) Expansion (Orifice) Tube
(10) Liquid Line
(11) Pressure Relief Valve
The variable displacement orifice tube (VDOT) system is comprised of the following components:
A variable displacement compressor (1)
A fixed expansion tube (5)
This system matches the air conditioning demands under all modes without cycling. The basic compressor mechanism is a variable angle wobble-plate with five cylinders. The five cylinders are oriented around a common axis. The center of control of the compressor displacement is the control valve. The control valve is actuated by a bellows. The control valve is located in the rear head of the compressor (1) that senses compressor suction pressure. the crankcase-suction pressure differential controls the following conditions:
The wobble-plate angle
The compressor displacement
When the A/C capacity demand is high, the suction pressure will be above the control point. The valve performs the following functions:
Maintains a bleed discharge gas into the crankcase
Closes off a passage from the crankcase to the suction plenum
The angle of the wobble-plate is controlled by a force balance on the five pistons. A slight elevation of the crankcase suction pressure differential creates a total force on the pistons. The force on the pistons produces a movement about the wobble-plate pivot pin that reduces the plate angle.
Refrigerant R-134a
Caution: Avoid breathing the A/C Refrigerant 134a (R-134a) and the lubricant vapor or the mist. Exposure may irritate the eyes, nose, and throat. Work in a well ventilated area. In order to remove R-134a from the A/C system, use service equipment that is certified to meet the requirements of SAE J 2210 (R-134a recycling equipment). If an accidental system discharge occurs, ventilate the work area before continuing service. Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.
Refrigerant performs the following functions in the air conditioning system:
Absorbs heat
Carries heat
Releases heat
These vehicles use Refrigerant-134a (R-134a). Refrigerant-134a is a nontoxic, nonflammable, clear, colorless liquefied gas.
Handling Compressor Oil
Use approved compressor oil from a closed, sealed container. When adding refrigerant oil, the transfer device and container should be clean and dry to minimize the possibility of contamination. Refrigerant oil is moisture-free and will readily absorb moisture from the air. Do not open the oil container until the service procedure requires oil. Cap the oil immediately after use. Always store compressor oil in a closed sealed container. Compressor oil left in open or improperly sealed containers will absorb moisture. Do not reuse oil that has been removed from the refrigeration system. Dispose of used oil properly, according to local regulations.
Handling Air Conditioning (A/C) Compressor
Do not strike, drop, or turn the compressor upside down. If the compressor is knocked over or turned upside down, rotate the compressor's clutch 5-6 times by hand to circulate the oil which has settled in the cylinder. Sudden rotation with oil in the cylinder can cause valve damage and adversely affect durability.
Handling of Refrigerant Lines and Fittings
Ensure that the metal lines do not exhibit the following conditions. This will prevent the loss of system capacity due to line restriction:
Dents
Kinks
Do not bend the flexible hose line to a radius of more than 4 times the diameter of the hose.
Do not allow the flexible hose line to come within a distance of 63.5 mm (2 ½ in) of the exhaust manifold.
Inspect the flexible hose lines regularly. Replace the flexible hose line with new hose if one of the following conditions exist:
Leaks
Brittleness
Deterioration
Before disconnecting any fitting in the refrigeration system, discharge all of the Refrigerant-134a.
Once you open a refrigerant line to the atmosphere, cap or tape the line immediately. This will prevent any of the following items from entering the line:
Moisture
Dirt
Use the proper wrenches when you make connections on the O-ring fittings. Back-up the opposing fitting with a wrench in order to prevent distortion of the following areas:
The connecting lines
The components
Tighten all of the tubing connections to the specified torque. Too much or too little torque may result in the following conditions:
Loose joints
Deformed joint parts
Refrigerant leakage
An inoperative A/C system
Ensure that the O-rings and the seats are in perfect condition. A burr or a piece of dirt may cause a refrigerant leak.
Install new O-rings that you have lubricated with the mineral base 525 viscosity refrigerant oil. Do not use polyalkylene glycol (PAG) synthetic oil. Do not wipe the threads with a cloth.
Keep PAG synthetic refrigerant oil off fitting threads. Long term contact of PAG synthetic oil on threads may cause future disassembly difficulties. Flush threads of fitting with mineral base 525 viscosity refrigerant oil. Do not use PAG synthetic oil. Do not wipe threads with a cloth.
09-20-2005 | 11:39 PM
#3
TECH Veteran
Joined: Dec 2004
Posts: 4,012
Likes: 1
From: Beaumont, TX
More:
Maintaining Chemical Stability
The chemical stability of the refrigeration system plays an important role in the efficient operation and longevity of the A/C system.
When air, moisture or particulate contamination are introduced into the refrigeration system, the following results will occur:
The chemical stability of R-134a and polyalkylene glycol (PAG) synthetic lubricant will change.
The pressure/temperature symmetry will change.
The A/C system efficiency will be diminished.
Internal A/C system parts may corrode and/or wear in an abnormal manner.
Use the following general practices to maintain chemical stability in the refrigeration system:
Wipe away dirt and/or oil before you break a refrigerant connection. This will reduce the possibility of particulate contamination.
Cap, plug or tape both sides of an open connection as soon as possible. This will minimize the amount of dirt and moisture entering the system.
Ensure that the following remain clean and dry:
The tools being used for the repair
The surrounding area of the repair
The hoses and connectors for the ACR4 machine or manifold gage set
The replacement parts
When adding polyalkylene glycol (PAG) lubricant, ensure the transfer device and the container remain clean and dry to minimize moisture intrusion.
Do not leave the A/C system open any longer than necessary.
Before recharging an A/C system that has been opened, properly evacuate and vacuum test the system.
Service parts are dehydrated and sealed prior to shipping. Retain the parts in their sealed packages until you are ready to use them.
Ensure the parts are at room temperature before opening the packages. This prevents condensation on the parts from humidity in the atmosphere.
Attach the A/C service equipment quick-connects as soon as possible after removing the service caps.
Refrigerant Oil Distribution
Notice: Use only Polyalkylene Glycol Synthetic Refrigerant Oil (PAG) for internal circulation through the R-134a A/C system and only 525 viscosity mineral oil on fitting threads and O-rings. If lubricants other than those specified are used, compressor failure and/or fitting seizure may result.
The following information should be used to service the air conditioning (A/C) system:
A/C system internal lubricant (including compressor) use GM P/N 12345923 or equivalent.
A/C system O-ring and fitting lubricant use GM P/N 12301108 or equivalent.
Condenser Description
The condenser is located in front of the radiator.
The condenser is made up of aluminum tubing and aluminum cooling fins, which allows rapid heat transfer for the refrigerant. Compressed refrigerant enters the condenser in a high pressure, high temperature vapor state. As the refrigerant flows through the condenser, the heat of the refrigerant is transferred to the ambient air passing through the condenser. Cooling the refrigerant causes the refrigerant to condense and change from a vapor to a liquid. Refrigerant exiting the condenser is in a high-pressure, medium temperature liquid state.
Evaporator Description
The evaporator cools and dehumidifies air before the air enters the passenger compartment. The following events occur in the evaporator:
Low-pressure, low temperature liquid/vapor refrigerant enters the evaporator.
The refrigerant flows through the evaporator's tubing.
The refrigerant evaporates.
The refrigerant exits the evaporator as low-pressure, low temperature, mostly vapor refrigerant.
As the refrigerant evaporates, the refrigerant absorbs heat from the air flowing over the evaporator.
As the process of heat loss from the air to the evaporator core is taking place, any moisture (humidity) in the air condenses on the outside surface of the evaporator core and the moisture drains off as water.
Expansion (Orifice) Tube Description
(1) Short Screen (Outlet)
(2) O-Ring
(3) Long Screen (Inlet)
The plastic expansion (orifice) tube includes the following components:
A mesh screen
An orifice
The expansion (orifice) tube is located in the evaporator inlet pipe at the liquid line connection. The tube restricts the high pressure liquid refrigerant in the liquid line. The tube meters the refrigerant flow to the evaporator as a low pressure liquid.
The expansion tube and the orifice have filter screens. The filter screens which protect the tube from contamination on both the inlet and the outlet sides.
The refrigerant in the system flows from the high pressure side of the tube to the low pressure side when the following conditions exist:
The engine is OFF.
The A/C is running.
The refrigerant will flow until the pressure is equalized. You may hear a faint hissing sound for 30-60 seconds. This sound is normal.
Accumulator Description
(1) Refrigerant Vapor Inlet
(2) Inlet
(3) Baffle
(4) Internal Tube
(5) Desiccant Bag
(6) Filter
(7) Oil Bleed Hole Location--In the Tube
(8) Outlet
The sealed accumulator is connected to the evaporator outlet pipe. The accumulator stores the refrigerant (vapor and liquid) and the oil from the evaporator. A desiccant at the accumulator bottom dries any moisture in the system. An oil bleed hole at the accumulator outlet pipe end provides the oil return path to the compressor. The accumulator is not serviceable and should only be replaced when leaking due to the following conditions:
Perforation
A damaged sealing area
Damaged fastener threads
Outside air has entered the system for extended periods of time
Compressor Description
V7 Compressor
(1) Shaft Nut
(2) Clutch Hub Key
(3) Clutch Plate and Hub
(4) Clutch Rotor and Bearing Snap Ring
(5) Clutch Rotor Bearing
(6) Clutch Rotor
(7) Cluch Coil
(8) Compressor Shaft Seal and Snap Ring
(9) Compressor Control Valve
(10) Compressor Control Valve Retaing Ring
(11) Compressor
(12) Pressure Relief Valve
(13) Suction Port Screen
(14) Special R-134a Suction Port
(15) Seal Washers
(16) Special R-134a Discharge Port
The V7 compressor is a variable displacement compressor that can match the automotive air conditioning demand under all conditions without cycling. The basic compressor mechanism is a variable angle wobble-plate with seven axially oriented cylinders. A bellows actuated control valve located in the rear head of the compressor senses the compressor suction pressure and is the center of control for the compressor displacement. The crankcase-suction differential controls both the wobble-plate and the compressor displacement. When the A/C capacity demand is high, the suction pressure will be above the control point. The control valve will maintain a bleed from crankcase to suction which causes no crankcase-suction pressure differential giving the compressor maximum displacement. When the A/C capacity demand is lower and the suction pressure reaches the control point, the valve will bleed discharge gas into the crankcase and close of a passage from the crankcase to the suction plenum. The wobble-plate angle is controlled by a force balance on the seven pistons. A slight increase in the crankcase-suction pressure differential creates a force on the pistons. This results in a movement of the wobble-plate pivot pin that reduces the plate angle.
The compressor has a unique lubrication system. The crankcase-suction bleed is routed through the rotating wobble-plate for lubrication of the wobble-plate bearing. The rotation acts an oil separator, removing some of the oil from the crankcase-suction bleed, and rerouting the oil to the crankcase where the oil can lubricate the compressor mechanism.
O-Ring/Flat Washer Description
Install new approved service replacement air conditioning O-ring(s) and flat washers whenever a joint or fitting is disassembled.
Some vehicles use flat sealing washers and O-ring(s) to seal the refrigerant system. The flat washers are used on block fittings of refrigerant components. The O-ring(s) is used to seal the refrigerant tubes.
The O-ring fitting consists of:
An aluminum alloy, externally threaded fitting which is welded to an aluminum tube.
A free-spinning internally threaded nut.
An aluminum tube end which accommodates the O-ring(s).
Verify that the flat washers or O-ring(s) have not been damaged prior to installation. Replace damaged parts.
Coat O-ring(s) and flat washers with the approved refrigerant oil.
Failure to use the proper service replacement parts and procedures may result in a leak.
Service Caps Seal
The primary seal for the service ports is the sealing cap. The cap contains a specially designed O-ring or gasket which provides a leak free seal. Should the cap be loose, missing, or the wrong usage, a loss of refrigerant could result.
Maintaining Chemical Stability
The chemical stability of the refrigeration system plays an important role in the efficient operation and longevity of the A/C system.
When air, moisture or particulate contamination are introduced into the refrigeration system, the following results will occur:
The chemical stability of R-134a and polyalkylene glycol (PAG) synthetic lubricant will change.
The pressure/temperature symmetry will change.
The A/C system efficiency will be diminished.
Internal A/C system parts may corrode and/or wear in an abnormal manner.
Use the following general practices to maintain chemical stability in the refrigeration system:
Wipe away dirt and/or oil before you break a refrigerant connection. This will reduce the possibility of particulate contamination.
Cap, plug or tape both sides of an open connection as soon as possible. This will minimize the amount of dirt and moisture entering the system.
Ensure that the following remain clean and dry:
The tools being used for the repair
The surrounding area of the repair
The hoses and connectors for the ACR4 machine or manifold gage set
The replacement parts
When adding polyalkylene glycol (PAG) lubricant, ensure the transfer device and the container remain clean and dry to minimize moisture intrusion.
Do not leave the A/C system open any longer than necessary.
Before recharging an A/C system that has been opened, properly evacuate and vacuum test the system.
Service parts are dehydrated and sealed prior to shipping. Retain the parts in their sealed packages until you are ready to use them.
Ensure the parts are at room temperature before opening the packages. This prevents condensation on the parts from humidity in the atmosphere.
Attach the A/C service equipment quick-connects as soon as possible after removing the service caps.
Refrigerant Oil Distribution
Notice: Use only Polyalkylene Glycol Synthetic Refrigerant Oil (PAG) for internal circulation through the R-134a A/C system and only 525 viscosity mineral oil on fitting threads and O-rings. If lubricants other than those specified are used, compressor failure and/or fitting seizure may result.
The following information should be used to service the air conditioning (A/C) system:
A/C system internal lubricant (including compressor) use GM P/N 12345923 or equivalent.
A/C system O-ring and fitting lubricant use GM P/N 12301108 or equivalent.
Condenser Description
The condenser is located in front of the radiator.
The condenser is made up of aluminum tubing and aluminum cooling fins, which allows rapid heat transfer for the refrigerant. Compressed refrigerant enters the condenser in a high pressure, high temperature vapor state. As the refrigerant flows through the condenser, the heat of the refrigerant is transferred to the ambient air passing through the condenser. Cooling the refrigerant causes the refrigerant to condense and change from a vapor to a liquid. Refrigerant exiting the condenser is in a high-pressure, medium temperature liquid state.
Evaporator Description
The evaporator cools and dehumidifies air before the air enters the passenger compartment. The following events occur in the evaporator:
Low-pressure, low temperature liquid/vapor refrigerant enters the evaporator.
The refrigerant flows through the evaporator's tubing.
The refrigerant evaporates.
The refrigerant exits the evaporator as low-pressure, low temperature, mostly vapor refrigerant.
As the refrigerant evaporates, the refrigerant absorbs heat from the air flowing over the evaporator.
As the process of heat loss from the air to the evaporator core is taking place, any moisture (humidity) in the air condenses on the outside surface of the evaporator core and the moisture drains off as water.
Expansion (Orifice) Tube Description
(1) Short Screen (Outlet)
(2) O-Ring
(3) Long Screen (Inlet)
The plastic expansion (orifice) tube includes the following components:
A mesh screen
An orifice
The expansion (orifice) tube is located in the evaporator inlet pipe at the liquid line connection. The tube restricts the high pressure liquid refrigerant in the liquid line. The tube meters the refrigerant flow to the evaporator as a low pressure liquid.
The expansion tube and the orifice have filter screens. The filter screens which protect the tube from contamination on both the inlet and the outlet sides.
The refrigerant in the system flows from the high pressure side of the tube to the low pressure side when the following conditions exist:
The engine is OFF.
The A/C is running.
The refrigerant will flow until the pressure is equalized. You may hear a faint hissing sound for 30-60 seconds. This sound is normal.
Accumulator Description
(1) Refrigerant Vapor Inlet
(2) Inlet
(3) Baffle
(4) Internal Tube
(5) Desiccant Bag
(6) Filter
(7) Oil Bleed Hole Location--In the Tube
(8) Outlet
The sealed accumulator is connected to the evaporator outlet pipe. The accumulator stores the refrigerant (vapor and liquid) and the oil from the evaporator. A desiccant at the accumulator bottom dries any moisture in the system. An oil bleed hole at the accumulator outlet pipe end provides the oil return path to the compressor. The accumulator is not serviceable and should only be replaced when leaking due to the following conditions:
Perforation
A damaged sealing area
Damaged fastener threads
Outside air has entered the system for extended periods of time
Compressor Description
V7 Compressor
(1) Shaft Nut
(2) Clutch Hub Key
(3) Clutch Plate and Hub
(4) Clutch Rotor and Bearing Snap Ring
(5) Clutch Rotor Bearing
(6) Clutch Rotor
(7) Cluch Coil
(8) Compressor Shaft Seal and Snap Ring
(9) Compressor Control Valve
(10) Compressor Control Valve Retaing Ring
(11) Compressor
(12) Pressure Relief Valve
(13) Suction Port Screen
(14) Special R-134a Suction Port
(15) Seal Washers
(16) Special R-134a Discharge Port
The V7 compressor is a variable displacement compressor that can match the automotive air conditioning demand under all conditions without cycling. The basic compressor mechanism is a variable angle wobble-plate with seven axially oriented cylinders. A bellows actuated control valve located in the rear head of the compressor senses the compressor suction pressure and is the center of control for the compressor displacement. The crankcase-suction differential controls both the wobble-plate and the compressor displacement. When the A/C capacity demand is high, the suction pressure will be above the control point. The control valve will maintain a bleed from crankcase to suction which causes no crankcase-suction pressure differential giving the compressor maximum displacement. When the A/C capacity demand is lower and the suction pressure reaches the control point, the valve will bleed discharge gas into the crankcase and close of a passage from the crankcase to the suction plenum. The wobble-plate angle is controlled by a force balance on the seven pistons. A slight increase in the crankcase-suction pressure differential creates a force on the pistons. This results in a movement of the wobble-plate pivot pin that reduces the plate angle.
The compressor has a unique lubrication system. The crankcase-suction bleed is routed through the rotating wobble-plate for lubrication of the wobble-plate bearing. The rotation acts an oil separator, removing some of the oil from the crankcase-suction bleed, and rerouting the oil to the crankcase where the oil can lubricate the compressor mechanism.
O-Ring/Flat Washer Description
Install new approved service replacement air conditioning O-ring(s) and flat washers whenever a joint or fitting is disassembled.
Some vehicles use flat sealing washers and O-ring(s) to seal the refrigerant system. The flat washers are used on block fittings of refrigerant components. The O-ring(s) is used to seal the refrigerant tubes.
The O-ring fitting consists of:
An aluminum alloy, externally threaded fitting which is welded to an aluminum tube.
A free-spinning internally threaded nut.
An aluminum tube end which accommodates the O-ring(s).
Verify that the flat washers or O-ring(s) have not been damaged prior to installation. Replace damaged parts.
Coat O-ring(s) and flat washers with the approved refrigerant oil.
Failure to use the proper service replacement parts and procedures may result in a leak.
Service Caps Seal
The primary seal for the service ports is the sealing cap. The cap contains a specially designed O-ring or gasket which provides a leak free seal. Should the cap be loose, missing, or the wrong usage, a loss of refrigerant could result.
09-21-2005 | 05:43 PM
#4
Thanks that link helped out, i think i'm going to change the reciever drier as well, pretty much for waranty purposes, as well as the guy i bought it off of already has the parts so figure might as well do it all at once, thanks for the info tho
