Contents: Air conditioning system ⤓ Checking the refrigerant charge level ⤓ Adding refrigerant ⤓ Heating system ⤓ Eliminating Air Conditioning Odors ⤓
Air conditioning system
Warning! The air conditioning system is under constant high pressure. Never disconnect refrigeration lines or remove any system components without first discharging the system. Discharging the air conditioning system must be done by an experienced technician in a car service workshop. Always wear safety glasses when disconnecting refrigeration lines!
1. The following checks should be performed on a regular basis to maintain the air conditioning system in good condition:
- a) Check the condition of the compressor drive belt. If defects or signs of wear are detected, replace it (see Chapter Settings and ongoing maintenance);
- b) Check the tension of the drive belt and adjust it if necessary (see Chapter Settings and ongoing maintenance);
- c) Check the refrigeration line hoses for cracks, swelling, signs of hardening and aging of the rubber, assess the condition of the nipple connections. Replace defective components;
- d) Check the condenser heat exchanger plates for insect remains, old leaves and other debris stuck between them. If necessary, clean the gaps with a thin brush or blow them out with compressed air;
- e) Check the system charge level;
2. The air conditioning system should be turned on for at least 10 minutes at least once a month (even in winter). Long periods of inactivity of the air conditioning system will cause the sealing rings and cuffs of the connecting line to harden and fail.
3. Existing leaks in the tract are best revealed by increasing the operating parameters of the system (temperature and pressure) - leave the air conditioner on for 5-10 minutes with the engine running. The sources of leaks can be identified by oil drips.
4. Due to the complexity of the system design and the need to use special equipment, its maintenance, in-depth diagnostics and repairs are beyond the skill level of the average amateur mechanic and must be performed in a car service workshop. The car owner is only competent to perform the simplest checks and replacements listed below in this Section.
5. If the system does not function at all, check the condition of the corresponding fuse and relay.
6. The most common cause of malfunction of the air conditioner is a decrease in the charge level of the refrigerant oil. The following simple tests will allow you to quickly identify signs of a decrease in the refrigerant level.
Checking the refrigerant charge level
1. Warm up the engine to normal operating temperature.
2. Turn on the air conditioner to maximum cooling capacity. Select the maximum fan speed. Open the doors to avoid cyclic shutdowns of the system when cooling the closed air volume in the cabin.
3. The activation of the A/C compressor clutch is accompanied by a clearly audible click, after which the central part of the clutch should begin to rotate. After the system temperature reaches the operating value, feel the two tubes connected to the evaporator on the bulkhead of the engine compartment.
4. The thinner tube going to the evaporator from the condenser outlet fitting should be quite cold to the touch. The thicker tube going from the evaporator outlet fitting back to the compressor should be a little colder (2-6 degrees). If the outlet tube is noticeably warmer to the touch than the inlet tube, the system needs recharging. Insert a thermometer into the outlet air duct through the central deflector on the instrument panel. When the air conditioning is on, the temperature of the air coming out of the deflector should be 2-4.5 degrees lower than the ambient temperature (up to 4.5°C). In very hot weather (above 40°C), an increase in the outlet temperature to 15.7°C is permissible, but not more. If the air conditioner does not provide the required intensity of air cooling, the system should be recharged. For a more detailed diagnosis of the system condition, the car should be driven to a specialized workshop.
5. Look into the inspection window on the receiver-dryer assembly cover - foaming of the refrigerant inside the receiver indicates a drop in its level. In hot weather, bubbles in the inspection window may be present even with a normal level of the working fluid - after the system is turned off, foaming should stop.
Adding refrigerant
Attention! Since 1994, the air conditioning systems on all models have been converted from R-12 refrigerant to environmentally friendly R-134a. Due to the difference in operating characteristics, the refrigerants are not interchangeable. In addition, the design of the nipple units and nozzles to the cylinders does not allow the accidental addition of the wrong type of oil to the system. When replacing components, the system should be replenished with exactly the same amount of refrigerant of the corresponding grade that was lost when the component was removed. Before filling the system, carefully read the instructions printed on the cylinder.
In many regions, the free sale of R-12 refrigerant may be prohibited and the system must be filled in a specialized service station. R-134a refrigerant can be purchased at almost any automotive chemical store.
1. Obtain a standard R-134a charging kit - ask at auto parts stores. The kit includes a 14 ounce can of refrigerant oil, a valve nozzle, and a piece of hose that connects between the valve and the low-pressure service port of the refrigeration system. The charging service port is usually included in the large tubing line of the refrigeration system that runs to the engine compartment bulkhead. Since one can of oil may not be enough to fully charge the system, it makes sense to buy a couple just in case. Make sure that at least one of the cans has the oil tinted red, which will allow you to quickly identify refrigerant leaks if they occur.
Attention! Never fill the system with more than two cans of refrigerant!
2. In accordance with the manufacturers instructions, connect the charging kit to the LOW PRESSURE portion of the refrigeration line.
3. Close the valve on the adapter and screw the latter onto the head of the can, having first checked that the sealing ring/rubber gasket is present.
Attention! Be sure to wear protective glasses!
4. Remove the dust cap from the low-pressure part of the refrigeration line and connect the charging kit hose equipped with a quick-connect connector to it.
Note: The design of the nipple assemblies does not allow the set to be connected to the high-pressure part of the tract.
5. Warm up the engine to normal operating temperature and turn on the A/C. Make sure that the charging kit hose does not come into contact with the cooling fan blades or other moving components in the engine compartment.
6. By rotating the valve nozzle, pierce the head of the canister, thereby opening the supply of refrigerant (you should hear a characteristic sound of escaping gas). During the entire charging process, hold the canister strictly vertically, shaking it from time to time. Charging should be interrupted when the temperatures of the inlet and outlet pipes of the evaporator become equal. Between charging series, make a pause necessary for stabilization of the system.
Note: Never fill the system with more than two refrigerant canisters! To prevent the canister from freezing during filling, wrap it in a towel soaked in warm water.
7. If you have an accurate thermometer at hand, insert it through the deflector into the central air duct of the air conditioner and monitor the temperature of the air supplied to the cabin.
8. When the can is empty, close the valve and disconnect the hose from the low-pressure fitting of the system. Immediately put the dust cap on the fitting.
9. Disconnect the valve nozzle from the cylinder, if necessary, move it to the second cylinder and continue filling. After completing the procedure, place the unfinished cylinder vertically on the rack and use it to recharge the system as needed.
Heating system
1. If the heater does not provide adequate heating of the air supplied to the passenger compartment, the reason for such failure may be one of the following:
- a) The thermostat is stuck open, preventing the engine coolant supplied to the heater heat exchanger from heating up to normal temperature. Replace the thermostat (see Section Checking the proper functioning and thermostat);
- b) There is a blockage in the cooling tract, which blocks the supply of coolant to the heater heat exchanger. Feel the hoses connected to the pipes on the rear bulkhead of the engine compartment - both of them should be hot, otherwise the tract is blocked (the hoses, heat exchanger, or heater control flap are blocked). Disconnect the hoses and perform a reverse-flow flush of the heat exchanger. Also flush both hoses;
- c) If it is not possible to restore the patency of the heat exchanger by flushing, it should be replaced (see Section Replacing the electric motor of the heater fan drive).
2. If the heater fan speed does not correspond to the selected position of the corresponding switch on the system control panel, check the condition of the fuse, connecting wiring, relay, switch and resistor assembly (see Section Replacing the electric motor of the heater fan drive).
3. If there is no air outlet through the deflectors at all, take the following steps:
- a) Turn on the ignition and activate the heater fan. Press your ear to the deflector and try to determine by ear whether the drive motor is functioning;
- b) If there are no sounds confirming the correct operation of the motor and the resistive assembly is in order, the motor should be replaced (see Section Replacing the electric motor of the heater fan drive).
4. Wetting of the carpet on the floor under the heater heat exchanger, or steam escaping through the air duct deflectors indicate heat exchanger leaks. Remove the heat exchanger (see Section Removal and installation the heater heat exchanger) and replace it with a new one (the heater heat exchanger cannot be repaired).
5. Check the drain hose coming from the heater/evaporator assembly and running along the right side of the bulkhead for leaks. A blockage in this hose can cause steam to leak from the air vents when the heater is turned on.
Eliminating Air Conditioning Odors
1. Unpleasant odors that often occur when the air conditioner is turned on are caused by the formation of mold colonies on the evaporator heat exchanger plates. A warm, humid environment creates favorable conditions for the emergence and development of fungal microorganisms.
2. Access to the evaporator heat exchanger on most models is extremely limited. The procedure for guaranteed complete mold removal, performed in a car service workshop, is quite labor-intensive, time-consuming and requires the use of strong disinfectants. In principle, a fairly effective treatment can be performed at home by the car owner himself.
3. Special disinfectants in aerosol packaging designed for servicing air conditioning systems can be purchased at almost any car accessory store. It should be remembered that the price of the product is usually directly proportional to its effectiveness. Switch the system to closed air circulation mode and turn on the heater fan at maximum speed for ten minutes. In order to dry the system, turn on the heating at maximum intensity. Disconnect the wiring from the compressor in order to prevent it from triggering.
4. The product is usually supplied through a long hose. Remove the resistor assembly of the heater fan drive electric motor (see Section Replacing the electric motor of the heater fan drive), insert the nozzle of the feeder into the resulting hole and move it to the left, directing it at the evaporator heat exchanger. The product is fed in accordance with the manufacturer's instructions. Try to treat the entire surface of the heat exchanger as completely as possible. The duration of each treatment cycle and the intervals between series must be indicated on the container label.
5. The best preventive measure against the formation of mold colonies in the evaporator heat exchanger is to regularly check the patency of the drain tube, as well as briefly turn on the condensate removal mode after each long trip with the air conditioner running in order to dry the evaporator.