The R-134a liquid refrigerant is highly volatile. A drop on the skin of your hand could result in localized frostbite. When handling the refrigerant,be sure to wear gloves.
If the refrigerant splashes into your eyes, wash them with clean water immediately. It is standard practice to wear goggles or glasses to protectyour eyes, and gloves to protect your hands.
The R-134a container is a highly pressurized vessel. Never leave it in a hot place, and check that the storage temperature is below 52°C (126°F)
A halide leak detector is often used to check the system for refrigerant leakage. Bear in mind that R-134a, upon coming into contact with flame (this detector burns like propane to produce a small flame), produces phosgene,a toxic gas.
Use only recommended lubricant for R-134a A/C system and components. If lubricants other than recommended one used, system failure may occur.
The PAG lubricant absorbs moisture from the atmosphere at a exceptionally fast rate and moisture can damage the A/C system, therefore the followingprecautions must be observed:
When removing refrigerant components from a vehicle, cap immediately the components to prevent A/C system from the entry of moisture.
When installing refrigerant components to a vehicle, do not remove the cap until just before connecting the components.
Complete the connection of all refrigerant tubes and hoses without delay to prevent the A/C system from entry of moisture.
Use the recommended lubricant from a sealed container only.
If accidental system discharge occurs, ventilate the work area before resuming service.
Lubricate O-ring fittings with compressor oil for easy tightening and to prevent leaking of refrigerant gas.
Tighten the nut using two wrenches to avoid twisting the tube.
Tighten the O-ring fittings to the specified torque.
Check for missing or damaged O-ring (Use only specified one) and lubricate with compressor oil.
Tighten the nut or bolt by pushing the side pipe.
Tighten the nut or bolt to the specified torque.
When connecting the manifold gauge set test hoses, be sure to observe all safety precautions.
Close both hand valves of the manifold gauge fittings.
Install the charging hoses of the gauge set to the fittings.
Connect the low-pressure hose to the low-pressure service port, and the high-pressure hose to the high-pressure service port.
Tighten the hose nuts by hand.
Fitting for attaching the manifold gauge set are located on the compressor and the high pressure hose.
It is necessary to evacuate the air conditioning system any time the system has been opened. Evacuation is necessary to rid the system of all air and moisture that may have been allowed to enter the unit. After installation of a component, the system should be evacuated for approximately 15 minutes. A component in service that has been opened for repair should be evacuatedfor 30 minutes.
Engine should be off.
Connect a manifold gauge set to the compressor gauge fittings. Close both high and low pressure valves.
Make sure the refrigerant has been discharged from the system.
Connect the center hose of the gauge set to the vacuum pump inlet.
Start the vacuum pump and then open the high and low manifold pressure valves.
Close both the manifold valves and stop the vacuum pump.
Charge system with a can or refrigerant [about 0.4 kg (0.9 lb)]. Refer to Charging Refrigerant.
Check for refrigerant leakage with a leak detector. Repair any leakage found. Refer to Checking Refrigerant Leak.
Discharge refrigerant again, and then evacuate the system. If no leaks are found, continue evacuating the system.
Start the vacuum pump.
Open both manifold pressure valves to obtain 94.39 kPa (0.96 kg/cm², 13.7 psi) of vacuum.
After the low pressure manifold gauge indicates as close to 94.39 kPa (0.96 kg/cm², 13.7 psi) as possible, continue evacuating for 15 minutes.
After evacuating for 15 minutes, close both manifold pressure valves and stop the vacuum pump. Disconnect the hose from the vacuum pump. The systemis now ready for charging.
Before connecting the valve to the refrigerant container, turn the handle fully counterclockwise.
Turn the disc counterclockwise until it reaches its highest position.
Connect the center hose to the valve fitting. Turn the disc fully clockwise by hand.
Turn the handle clockwise to make a hole in the sealed top.
Turn the handle fully counterclockwise to fill the center hose with air. Do not open the high and low-pressure hand valves.
Loosen the center hose nut connected to the center fitting of the manifold gauge.
Allow air to escape for a few seconds, and then tighten the nut.
This step is to charge the system through the low pressure side with refrigerant in a vapor state. When the refrigerant container is placed rightside up, refrigerant will enter the system as a vapor.
Install the refrigerant can tap valve as described in Handling the Refrigerant Service Tap Valve section.
Open the low pressure valve. Adjust the valve so that the low pressure gauge does not read over 412 kPa (4.2 kg/cm², 60 psi).
Put the refrigerant in a pan of warm water (maximum temperature 40°C or (104°F) to keep vapor pressure in the container slightly higher thanvapor pressure in the system.
Run the engine at fast idle, and operate the air conditioning.
Be sure to keep the container upright to prevent liquid refrigerant from being charged into the system through the suction side, resulting inpossible damage to the compressor.
Specified amount : 680±25g (1.49±0.06lb) |
Under any circumstances the refrigerant can must not be warmed in water heated to a temperature of over 52°C (126°F).
A blow torch or stove must never be used to warm up the can.
This step is to charge an empty system through the high pressure side with refrigerant in a liquid state. When the refrigerant container is heldupside down, refrigerant will enter the system as a liquid.
Never run the engine when charging the system through the high pressure side. Do not open the low pressure valve when the system is being chargedwith liquid refrigerant.
Close both high and low pressure valves completely after the system is evacuated.
Install the refrigerant can tap valve as described in "Handling Refrigerant Service Tap Valve" section.
Open the high pressure valve fully, and keep the container upside down.
Charge the system to the specified amount by weighing the refrigerant with a scale. Overcharging will cause the discharge pressure (high side) torise. Then, close the high pressure valve.
Specified amount : 680 ± 25 g (1.49 ± 0.6 lb) |
If the low pressure gauge does not show a reading, the system is restricted and must be repaired.
After the specified amount of refrigerant has been charged into system, close the manifold gauge valve.
Confirm that there are no leaks in the system by checking with a leak detector. Refer to Checking Refrigerant Leak.
Conducting a performance test prior to removing the manifold gauge is good service operation.
Total amount of oil in the system : 150 cc (9.1 fl.oz) |
The oil should be free from moisture, dust, metal filings, etc.
Do not mix oils.
The moisture content in the oil increases when exposed to the air for prolonged periods. After using, seal the container immediately.
Carefully check the hoses and lines, especially those located close to moving parts or sharp panel edges.
In order to use the device properly, read the manuals supplied by the manufacturer to perform the specified maintenance and inspections.
Check the torque on the connection fitting and, if too loose, tighten to the proper torque. Check for gas leakage with a leak detector.
If leakage continues even after the fitting has been retightened, discharge the refrigerant from the system, disconnect the fittings, and check its seatingface for damage. Always replace, even if the damage is slight.
Check compressor oil and add oil if required.
Charge the system and recheck for gas leaks. If no leaks are found, evacuate and charge the system.
Install the manifold gauge set.
Run the engine at 2,000 rpm and set the controls for maximum cooling and high blower speed.
Keep all windows and doors open.
Place a dry-bulb thermometer in the cool air outlet.
Place a psychrometer close to the inlet of the cooling unit.
Check that the reading on the high pressure gauge is 1,373-1,575 kPa (14-16 kg/cm², 199-228 psi). If the reading is too high, pour water on the condenser. If the reading to too low, cover the front of the condenser.
Check that the reading on the dry-bulb thermometer at the air inlet at 25-35°C (77-95°F).
Calculate the relative humidity from the psychrometric graph by comparing the wet-and dry-bulb reading of the psychrometer at the air inlet.
Measure the dry-bulb temperature at the cool air outlet, and calculate the difference between the inlet dry-bulb and outlet dry-bulb temperatures.
Check that the intersection of the relative humidity and temperature difference is within the block hard line. If the intersection is within theblock hard line, cooling performance is satisfactory.
The test gauge indicators shown in the following chapter are to be used as typical examples of common problem, which you may need to diagnose.
GAUGE READINGS | OTHER SYMPTOMS | DIAGNOSIS | CORRECTION |
 | ● Discharge air: slightly cool ● Thermostatic switch (with thermistor): Low side gauge doesn't fluctuate with switch "ON" and "OFF" cycle. | Some air and moisture in system | 1. Leak test system. 2. Discharge refrigerant from system. 3. Repair leaks as located. 4. Replace receiver-drier. The drier is probably saturated with moisture. 5. Evacuate the system for at least 30 minutes. 6. Charge system with refrigerant. 7. Operate system and check performance. |
 | ● Discharge air: Becomes warm as low side cycles into vacuum. ● Discharge air: Becomes warm all the time during hot part of day. | Excessive moisture in system. | 1. Discharge refrigerant. 2. Replace receiver-drier. 3. Evacuate system with a vacuum pump. 4. Recharge system to proper capacity. 5. Operate system and check performance. |
 | ● Compressor: Cycles on and off too fast. ● Low side gauge: Not enough range shown on low side gauge. | Defective thermostatic switch | 1. Stop engine and turn air conditioning "OFF". 2. Replace thermostatic switch when installing new thermostatic switch. Make sure that thermister tube is installed in the same position and to the same depth in evaporator core as old switch tube. 3. Operate system and check. |
 | ● Compressor: low side pressure builds too high before compressor turns on (cycle "ON" point too high) | Faulty thermostatic switch | 1. Stop engine and turn air conditioning "OFF". 2. Repair or replace thermostatic switch with thermistor (make sure that all wiring is positioned so that no short circuiting can occurred). 3. Operate system and check performance. |
 | ● Discharge air: Slightly cool. | System slightly low on refrigerant. | 1. Check leaks. 2. Discharge refrigerant. 3. Repair leaks. 4. Check compressor oil level. 5. Evacuate system using a vacuum pump. 6. Charge system with refrigerant. 7. Operate system and check performance. |
 | ● Discharge air: Warm. | ● System very low on refrigerant. ● Possible leak in system. | 1. Check leaks. 2. Leak test compressor seal area very carefully. 3. Discharge refrigerant. 4. Check compressor oil level. 5. Evaporate system using a vacuum pump. 6. Charge system with refrigerant. 7. Operate system and check performance. |
 | ● Discharge air: Slightly cool. ● Expansion valve: Sweating or frost build up. | ● Expansion valve stuck closed. ● Screen plugged. ● Sensing bulb malfunction. | 1. Discharge system. 2. Discharge expansion valve, remove and inspect screen. 3. Clean and replace screen and reconnect screen. 4. Clean and replace screen and reconnect inlet line. 5. Evacuate system using a vacuum pump. 6. Charge system with refrigerant |
 | ● Discharge air: slightly cool. ● High side pipe: Cool and also shows sweating or frost. | Restriction in high side of system | 1. Discharge system. 2. Remove and replace receiver-drier, liquid pipes or other defective components. 3. Evacuate system using a vacuum pump. 4. Charge system with refrigerant. 5. Operate system and check performance. |
 | ● Compressor: Noisy | Compressor malfunction | 1. Isolate compressor. 2. Remove compressor cylinder head and inspect compressor. 3. Check compressor oil level. 4. Replace receiver-drier. 5. Operate system and check performance. |
 | ● Discharge air: Warm. ● High side pipe: Very hot | Malfunctioning condenser overcharge. | 1. Check for loose or worn fan belt. 2. Inspect condenser for clogged air passage. 3. Inspect condenser mounting for proper radiator clearance. 4. Check for refrigerant overcharge. 5. Operate system and check performance. |
 | ● Discharge air: Slightly cool. | Large amount of air and moisture. | 1. Discharge refrigerant from system. 2. Replace receiver-drier which may be saturated with moisture. 3. Evacuate system using vacuum pump. 4. Charge system with refrigerant. 5. Operate system and check performance. |
 | ● Discharge air: Warm. ● Evaporator: Sweating or frost. | Expansion valve stuck open | 1. Discharge system. 2. Replace expansion valve, making sure all contacts clean and secure. 3. Evacuate system using vacuum pump, then recharge system with refrigerant. 4. Operate system and check performance. |
Check that the belts are not damaged and fit properly into the pulley grooves.
When installing the V-ribbed belt, check that the V-ribes are properly aligned.
If noise or slippage is detected, check the belt for wear, damage, or breakage on the pulley contact surface, and check the pulley for scoring.Also check for the proper belt deflection measurement.
Apply 100 N (22 lbs.) force to the belt back midway between the pulleys as shown in the illustration, measure the amount of deflection with a tensiongauge.
Inspection | Adjustment | |||
New | Used | |||
For air conditioner compressor | Deflection mm (in.) | 11.7-15.3 (0.46-0.6) | 8.8-11.0 (0.35-0.43) | 12.5-14.3 (0.49-0.56) |
Tension (kg·f) | 50±10 | 75±10 | 50±5 | |
