1994 MAZDA MX-5 Workshop Manual

AIR CONDITIONER u Refilling Caution If there is too much refrigerant in the system, pressure cannot be fixed at an appropriate level to change the gas to a liquid. Do not overcharge the system. 1. Install the manifold gauge set. (Refer to page U-25.) 2. Connect the tap pin side of the charging hose to the air purge valve of the gauge set. 3. Connect the vacuum pump hose to the center joint of the gauge set. 4. Connect the vacuum pump hose to the vacuum pump. 5. Connect can puncture valves to a 4-way joint. 6. Fully open the can puncture valves and connect service cans to the valves. 7. Full close any can puncture valve that it is not connected to a service can. 8. Connect the 4-way joint to the charging hose that is con- nected the gauge set air purge valve. 9. Open only the center valve of the manifold gauge set. 10. Start the vacuum pump and let it run for 5 minutes. 11. After 5 minutes, close the center valve of the manifold gauge set. 12. Stop the vacuum pump. Warning Running the engine with the high-pressure-side valve open is dangerous. Pressure within the ser- vice cans will increase and the cans could ex- plode, scattering metal fragments and liquid refrigerant that can seriously injury you. Therefore, do not open the high-pressure-side valve while the engine is running. 13. Open the service can by using the can puncture valve. 14. Start the engine and actuate the A/C compressor. 15. Open the low-pressure-side valve and refill with refriger- ant until the bubbles in the sight glass disappear and the high and low-pressure readings of the manifold gauge set are within normal pressure limits. (Refer to page U-29.) 16. Stop the engine and the NC compressor. 17. Disconnect the high and low-pressure-side quick cou- plers from the charging valves that are connected to the high and low-pressure-side cooler pipes of the refriger- ant system. 18. Install the caps to the charging valves of the cooler pipes. 45UOUX-060 Gartner Banana

u AIR CONDITIONER Performance Test After finishing repairs, conduct a performance test of the air conditioning system as follows. 1. Connect the manifold gauge set. (Refer to page U-25.) 2. Start the engine and keep the engine speed at 1,500 rpm. 3. Operate the air conditioner at maximum cooling. 4. Open all windows and doors. 5. Place a dry-bulb thermometer in the center ventilator outlet. 6. Place a dry and wet thermometer close to the blower in- let. 7. Wait until the air conditioner outlet temperature stabi- lizes. If the high-pressure side becomes too high, pour cool water on the condenser. If it is too low, cover the front of the condenser. Stabilized condition Blower inlet temperature: 30-35°C (86-95°F) High-pressure side: 1.38-1.56 MPa (1 4.0-1 6.0 kgflcm*, 200-227 psi) 8. After the air conditioner stabilizes, read the dry and wet thermometer at the air inlet. 9. Calculate the relative humidity from the chart below by comparing the wet- and dry-bulb readings. Gartner Banana

AIR CONDITIONER u "C "F 26 24 22 20 18 16 14 12 10 40 59 60 70 RELATIVE HUMIDITY I ltem I Symptom 10. Read the dry thermometer at the air outlet, and calculate the difference between the inlet dry bulb and outlet dry bulb temperatures. 11. Verify that the intersection of the relative humidity and temperature difference is in the shaded zone. Checking Refrigerant Charge 1. Run the engine at a fast idle. 2. Operate the air conditioner at maximum cooling for a few minutes. 3. Determine the amount of refrigerant as shown below by observing the sight glass. 1 Bubbles present in sight glass 2 No bubbles present in sight glass Immediately after air conditioner turned OFF, refrigerant in sight glass stavs clear 141 When air conditioner turned OFF, re- frigerant foams, and then sight glass becomes clear -- Amount of refrigerant Insufficient refrigerant Action Check refrigerant pressure -- Too much or proper amount of refrig- erant Too much refrigerant Checking Refrigerant Pressure 1. Connect the manifold gauge set. (Refer to page U-25.) 2. Operate the engine at 1,500 rpm and set the air condi- tioner to maximum cooling. 3. Measure the low- and high-pressure sides. Turn air conditioner OFF, and watch bubbles (Refer to Items 3 and 4) Check refrigerant pressure Proper amount of refrigerant Stabilized condition Low-pressure side: 0.15-4.24 MPa {I .5--2.5 kgf/cm2, 22-35 psi) High-pressure side: 1.38-1.56 MPa (1 4.61 6.0 kgflcm*, 200-227 psi) Refrigerant amount normal Gartner Banana

u AIR CONDITIONER COOLING UNIT Removal 1 Installation 1. Discharge the refrigerant system. 2. Remove the glove compartment. (Refer to section S.) il 3. Remove in the order shown in the figure. Immediately plug all open fittings to keep moisture out of the system. 4. Install in the reverse order of removal. Position the unit so that its connections match those of the heater unit and blower unit. Apply clean compressor oil to the O-rings before connecting the fittings; do not ap- ply compressor oil to the fitting nuts. Tightening torque Inlet pipe: 10-19 N-m (1.0-2.0 kgfsm, 8-14 ft-lbf} Outlet pipe: 20-29 N-m (2.0-3.0 kgf-m, 15--21 ft-lbf} 5. Charge the refrigerant system. (Refer to page U-25.) 7.910.7 N.m {EO-110 kgfmn, 69.5-95.4 In4bf} 45uoux-071 1. Cooling unit 2. Sealing plate Disassembly / Assembly . . . . . . page U-31 U-30 Gartner Banana

AIR CONDITIONER u Disassembly 1 Assembly 1. Disassemble in the order shown in the figure. 1. Evaporator 3. Thermoswitch ................... ......... Inspection page U-32 On-vehicle Inspection page U-32 ................... 2. Expansion valve Inspection page U-32 ................... Assembly note below Assembly note Expansion valve Apply clean compressor oil to the O-rings before con- necting the fittings; do not apply compressor oil to the fit- ting nuts. Gartner Banana

AIR CONDITIONER On-vehicle Inspection Thermoswitch 1. Remove the glove compartment. (Refer to section S.) 2. Run the engine at idle. u 3. Turn off the ACS and set the fan switch to the fourth posi- tion to operate the blower fan for a few minutes. 4. After a few minutes, turn off the fan switch and stop the engine. Note The thermoswitch contacts will be open if the evapo- rator temperature is below 0°C (32°F). 5. Disconnect the thermoswitch connector and check for continuity between the switch terminals. I Terminals I Continuity I I A-B I Yes I - -- Inspection Thermoswitch 1. Immerse the sensing bulb in a container of ice water. 2. Check for continuity between terminals of the switch as specified. 3. If not as specified, replace the thermoswitch. Continuity ( Terminals I Temperature A-B Evaporator 1. Check the evaporator fins for blockage. If the fins are clogged, clean them with compressed air. Do not use water to clean the evaporator. 2. Check the fittings for cracks and other damage. Replace the evaporator if necessary. When installing a new evap- orator, add 50 ml (50 cc, 1.5 fl oz) of compressor oil to the A/C compressor. d Above 0°C {32OFj Below 0°C (32°F) Yes No Gartner Banana

AIR CONDITIONER u CONDENSER AND RECEIVER DRIER Removal 1 Installation 1. Raise the front of the vehicle at least 300 mm (11.8 in) and support it on safety stands. 2. Discharge the refrigerant system. 3. Remove the splash shield and air guide. 4. Remove in the order shown in the figure. Immediately plug any open fittings to keep moisture out of the system. 5. Install in the reverse order of removal. Apply clean compressor oil to the O-rings before connecting the - fittings; do not apply compressor oil to the fitting nuts. Tightening torque Receiver drier inlet and outlet: 10-19 N-m (1.0-2.0 kgf-m, 8-14 ft-lbf) Condenser inlet: 15-24 N.m (1.5-2.5 kgfsm, 11-18 ft-lbf} 6. Install the air guide and splash shield. 7. Charge the refrigerant system. (Refer to page U-25.) 1. Condenser 2. Receiver drier On-vehicle Inspection . . . . . . . . . page U-34 On-vehicle Inspection . . . . . . . . . page U-34 U-33 Gartner Banana

u AIR CONDITIONER On-vehicle Inspection Condenser 1. Check for oil stains on the condenser or fittings. 2. If staining is found at a fitting, replace the O-ring at the u fitting. 3. Charge the system and check for leaks. 4. If leakage is found at a fitting or the condenser, replace parts as necessary. 5. Check the condenser for the following: (1) Cracks or damage (2) Bent fins (3) Distorted or damaged condenser inlet or outlet 6. Repair or replace as necessary. If the condenser is re- placed, add 30 ml(30 cc, 0.9 fi oz} of compressor oil. Receiver drier 1. Check for oil stains on the fittings. 2. If staining is found, replace the O-ring at the fitting. 3. Charge the system and check for leaks. 4. If leakage is found, replace the receiver drier or piping. When replacing the receiver drier, add 10 ml I10 cc, 0.3 -, fl or) of compressor oil. Gartner Banana