Insufficient Cooling, No Cooling, Intermittent Cooling

Step 1 Checking refrigerant charge





1. Run the engine at a fast idle.
2. Operate the air conditioner at maximum cooling for a few minutes.





3. Observe the sight glass located at right front side of radiator to determine the amount of refrigerant as listed above.

Step 2 Checking refrigerant pressure
1. Connect the A/C manifold gauge set.
2. Operate the engine at 2,000 rpm and set the air conditioner to maximum cooling.





3. Measure the low - and high - pressure sides.

Normal pressure Low-pressure side:
21-43 psi (147-294 kPa) High-pressure side:
171-235 psi (1,177-1,619 kPa)





4. If the pressures are not as specified, refer to the chart above and check the system.

Case 1: Insufficient refrigerant Measured pressure

Low-pressure side: Less than 11.4 psi (78.5 kPa)
High-pressure side: 114-128 psi (785-883 kPa) Condition

Outlet air from vents not cold.

Bubbles seen in sight glass.

Step 1
1. Check for oil stains on the pipes, hoses and other parts. (Refer to illustration below.)
2. If oil staining is found at the connection of pipes or hoses, replace the O-ring; then, evacuate, charge, and test the system. Refer to the operating instructions of your refrigerant recovery/recycling/charging station for proper procedures.





3. If oil staining is not found, go to Step 2.

Step 2
1. Check for leakage from the following connection with a gas leak tester.
a. Inlet and outlet of condenser
b. Inlet and outlet of receiver/drier
c. Inlet and outlet of compressor
d. Sight glass
e. Inlet and outlet of cooling unit
2. If leakage is evident, go to Step 3.
3. If leakage cannot be found, evacuate, charge and test the system. Refer to the operating instructions of your refrigerant recovery/recycling/charging station for proper procedures.

Step 3
1. Check tightening torque of the connection where leak was detected.
2. If the connection is loose, tighten the connection to the specified torque; then evacuate, charge, and test the system Refer to the operating instructions of your refrigerant recovery/recycling/charging station for proper procedures.
3. If the connection is properly tightened, replace the O-ring; then evacuate, charge, and test the system. Refer to the operating instructions of your refrigerant recovery/recycling/charging station for proper procedures.

Case 2: Excessive refrigerant or insufficient condenser cooling Measured pressure
Low-pressure side: 35.6 psi (245 kPa) High-pressure side: 284 psi (1,962 kPa)

Condition

NOTICE
If the condenser fan does not operate when the air conditioner is operating, refer to Condenser fan does not operate before proceeding.

Step 1





1. Check the condenser for bent fins or damage.
2. If the condenser is OK, discharge the excess refrigerant. Refer to the operating instructions of your refrigerant recovery/recycling/charging station for proper procedures.

CAUTION
Always wear gloves and eye protection when discharging the refrigerant.

3. Verify that the refrigerant pressure is normal.

Case 3: Air in system Measured pressure

Low-pressure: Above 35.6 psi (245 kPa)
High-pressure: Above 327 psi (2,256 kPa) Condition

Insufficient cooling





Step 1 Discharge the refrigeration system. Refer to the operating instructions of your refrigerant recovery/recycling/charging station for proper procedures.

Step 2
Evacuate the system to remove all air from it. Refer to the operating instructions of your refrigerant recovery/recycling/charging station for proper procedures.

Step 3
Charge the system with refrigerant. Refer to the operating instructions of your refrigerant recovery/recycling/charging station for proper procedures.

Step 4
After charging, measure the refrigerant pressure. Refer to Checking Refrigerant Pressure.

Step 5
If the low-and high-pressure sides are still too high, replace the receiver/drier.

Case 4: Moisture in system Measured pressure

Low-pressure: 2.0 in Hg (50 mmHg): [Vacuum]
High-pressure: 100-213 psi (687-1,472 kPa) Condition

(Moisture in refrigeration system freezes in expansion valve and causes temporary blocking.
After time, ice melts and condition returns to normal.)

Step 1
Discharge the refrigeration system. Refer to the operating instructions of your refrigerant recovery/recycling/charging station for proper procedures.

Step 2





Evacuate the system to remove air and moisture from it. Refer to the operating instructions of your refrigerant recovery/recycling/charging station for proper procedures.

Step 3
Charge the system with refrigerant. Refer to the operating instructions of your refrigerant recovery/recycling/charging station for proper procedures.

Step 4
After charging, measure the refrigerant pressure. Refer to Checking Refrigerant Pressure.

Step 5
If the low-and high-pressure sides are still too high, replace the receiver/drier.

Case 5: No refrigerant circulation Measurement pressure

Low-pressure: 3.0 inHg (76 mmHg) [Vacuum]
High-pressure: Below 85 psi (589 kPa)

Condition
Refrigerant flow obstructed by moisture or dirt, causing freezing or blockage of expansion valve.

Step 1





1. Turn the air conditioner OFF for about 10 minutes. Turn the air conditioner ON to determine whether the blockage is due to moisture or dirt.
a. If caused by moisture: System will operate normally after being OFF for 10 minutes. (Ice melts and relieves blockage.)
b. If caused by dirt: System remains abnormal after being OFF 10 minutes. Go to Step 2.

Step 2





1. Remove the expansion valve.
2. Blow out the dirt with compressed air.
3. If unable to remove the dirt, replace the expansion valve.
4. Evacuate, charge, and test the system. Refer to the operating instructions of your refrigerant recovery/recycling/charging station for proper procedures.

Case 6: Expansion valve stuck open Measured pressure

Low-pressure: Above 35.6 psi (245 kPa)
High-pressure: 270-284 psi (1,864-1,962 kPa) Condition

Step 1





1. Check whether there is frost or heavy dew on the suction pipe (between cooling unit and compressor).
2. If neither is found, refer to Case 2: Excessive refrigerant or insufficient condenser cooling.
3. If either is found, replace the expansion valve.

Case 7: Faulty compressor Measured pressure

Low-pressure: 57-85 psi (392-589 kPa)
High-pressure: 100-142 psi (689-981 kPa)

Condition

No cooling Step 1





1. Run the engine at a fast idle.
2. Verify that the A/C compressor clutch is ON when the A/C switch and blower switch are ON.
3. If the A/C compressor clutch remains OFF, refer to A/C compressor clutch does not operate.