TIBURON(GK) >2005 > G 2.7 DOHC > Heating,Ventilation, Air Conditioning > General Information>Repair procedures  
ON-VEHICLE INSPECTION
This is a method in which the trouble is located by using a manifold gauge set. Read the manifold gauge pressure when the these conditions are established.
TEST CONDITIONS
Temperature at the air inlet with the switch set at RECIRC is 30~35°C (86~95°F)
Engine running at 1,500rpm
Blower speed control knob on "4" position
Temperature control knob on "COOL" position
It should be noted that the gauge indications may vary slightly due to ambient temperature conditions.
1.
Normally functioning refrigeration system.
Gauge reading :
Low pressure side :
0.15~0.25 MPa (21.8~36.3 psi, 1.5~2.5 kgf/cm²)
High pressure side :
1.37~1.57 MPa (199~228 psi, 14~16 kgf/cm²)

2.
Moisture present in refrigeration system.

Symptom seen in refrigeration system
Probable cause
Diagnosis
Remedy
During operation, pressure on low pressure side sometimes become a vacuum and sometime normal
Moisture entered in refrigeration system freezes at expansion valve orifice and temporarily stops cycle, but normal state is restored after a time when the ice melts
Drier in oversaturected state
Moisture in refrigeration system freezes at expansion valve orifice and block circulation of refrigerant
-
Raplace drier
-
Remove moisture in cycle through repeatedly evacuating air
-
Charge proper amount of new refrigerant

3.
Insufficient cooling

Symptom seen in refrigeration system
Probable cause
Diagnosis
Remedy
Pressure low on both low and high pressure sides
Insufficient cooling performance
Gas leakage at some place in refrigeration system
Insufficient refrigerant in system
Refrigerant leaking
-
Check for gas leakage with gas leak detector and repair if necessary
-
Charge proper amount of refrigerant
-
If indicated pressure value is near 0 when connected to gauge, create the vacuum after inspecting and repairing the location of the leak

4.
Poor circulation of refrigerant

Symptom seen in refrigeration system
Probable cause
Diagnosis
Remedy
Pressure low in both low and high pressure sides
Frost on tube from receiver to unit
Refrigerant flow obstructed by dirt in drier
Condenser clogged
Replace drier

5.
Refrigerant does not circulate

Symptom seen in refrigeration system
Probable cause
Diagnosis
Remedy
Vacuum indicated on low pressure side, very low pressure indicated on high pressure side
Frost or dew seen on piping before and after receiver/drier or expansion valve
Refrigerant flow obstructed by moisture or dirt in refrigeration system
Refrigerant flow obstructed by gas leakage from expansion valve
Refrigerant does not circulate
-
Check expansion valve
-
Clean out dirt in expansion valve by blowing with air
-
Replace drier
-
Evacuate air and charge new refrigerant to proper amount
-
For gas leakage from expansion valve, replace expansion valve

6.
Refrigerant overcharged or insufficient cooling of condenser

Symptom seen in refrigeration system
Probable cause
Diagnosis
Remedy
Press too high on both low and high pressure sides
Unable to develop sufficient performance due to excessive
Insufficient cooling of condenser
Excessive refrigerant in cycle → refrigerant overcharged
Condenser cooling → condenser fins clogged or condenser fan faulty
-
(1) Clean condenser
-
(2) Check cooling fan with fluid coupling operation.
-
(3) If (1) and (2) are in normal state, check amount of refrigerant
Charge proper amount of refrigerant

7.
Air present in refrigeration system

Symptom seen in refrigeration system
Probable cause
Diagnosis
Remedy
Press too high on both low and high pressure sides
The low pressure piping hot to the touch
Air entered in refrigeration system
Air present in refrigeration system
Insufficient vacuum purging
-
Check compressor oil to see if it is see if it is dirty or insufficient
-
Evacuate air and charge new refrigerant

8.
Expansion valve improperly

Symptom seen in refrigeration system
Probable cause
Diagnosis
Remedy
Pressure too high on both low and high pressure sides
Frost or large amount of dew on piping on low pressure side
Trouble in expansion valve
Excessive refrigerant in low pressure piping
Expansion valve opened too wide
-
Check expansion valve
-
Replace if defective

9.
Defective compression compressor

Symptom seen in refrigeration system
Probable cause
Diagnosis
Remedy
Pressure too high on low high pressure sides
Pressure too low to on high pressure side
Internal leak in compressor
Compression defective
Valve leaking or broken sliding parts
Repair or replace compressor

INSPECT FOR LEAKAGE OF REFRIGERANT
Always conduct a leak test with an electronic leak detector whenever leakage or refrigerant is suspected and when conducting service operations which are accompanied by disassembly or loosening or connection fittings.
In order to use the leak detector properly, read the manual supplied by the manufacturer.
1.
Check the torque on the connection fittings and, if too loose, tighten to the proper torque. Check for gas leakage with a leak detector.
2.
If leakage continues even after the fitting has been tightened, discharge the refrigerant from the system, disconnect the fittings, and check their seating faces for damage. Always replace, even if the damage is slight.
3.
Check the compressor oil and add oil if required.
4.
Charge the system and recheck for gas leaks. If no leaks are found, evacuate and charge the system again

A/C SYSTEM TESTS
Air conditioning refrigerant or lubricant vapor can irritate your eyes, nose, or throat.
Be careful when connecting service equipment.
Do not breathe refrigerant or vapor.
Compressed air mixed with R-134a forms a combustible vapor.
The vapor can burn or explode causing serious injury.
Never use compressed air to pressure test R-134a service equipment or vehicle air conditioning systems.
1.
Connect a R-134a refrigerant recover/recycling/charging station to the high-pressure service port and the low-pressure service port, following the equipment manufacturer s instructions.
2.
Insert a thermometer in the center vent.
Determine the relative humidity and air temperature.

3.
Test conditions :
A.
Avoid direct sunlight.
B.
Open the hood.
C.
Open the front doors.
D.
Set the temperature control dial on MAX COOL, the mode control switch on VENT and the recirculation control switch on RECIRCULATE.
E.
Turn the A/C switch on and the fan switch on MAX.
F.
Run the engine at 1,500 rpm.
G.
No driver or passengers in vehicle.
4.
After running the air conditioning for 10 minutes under the above test conditions, read the delivery temperature from the thermometer in the dash vent, the intake temperature near the blower unit behind the glove box and the high and low system pressure from the A/C gauges.
5.
To complete the chart
A.
Mark the delivery temperature along the vertical line
B.
Mark the intake temperature along the bottom line
C.
Draw a line straight up from the air temperature to the humidity
D.
Mark a point 10% above and 10% below the humidity level
E.
From each point
F.
Draw a horizontal line across the delivery temperature
G.
The delivery temperature should fall between the two lines
H.
Complete the low side pressure test and high side pressure test in the same way
I.
Any measurements outside the line may indicate the near for more further inspection

REFRIGERANT RECOVERY
Air conditioning refrigerant or lubricant vapor can irritate your eyes, nose, or throat.
Be careful when connecting service equipment.
Do not breathe refrigerant or vapor.
1.
Connect a R-134a refrigerant recovery/recycling/charging station(A) to the high-pressure service port(B) and the low-pressure service port(C), as shown, following the equipment manufacturer s instruction.

2.
Measure the amount of refrigerant oil removed from the A/C system after the recovery process is completed. Be sure to put the same amount of new refrigerant oil back into the A/C system before charging.
SYSTEM EVACUATION
Air conditioning refrigerant or lubricant vapor can irritate your eyes, nose, or throat.
Be careful when connecting service equipment.
Do not breathe refrigerant or vapor.
1.
When an A/C System has been opened to the atmosphere, such as during installation or repair, it must be evacuated using a R-134a refrigerant recover/recycling/charging station (If the system has been open for several days, the receiver/dryer should be replaced, and the system should be evacuated for several hours.)
2.
Connect a R-134a refrigerant recovery/recycling/charging station(A) to the high-pressure service port(B) and the low-pressure service port(C), as shown, following the equipment manufacturer s instruction. Evacuate the system.

3.
If the low-pressure does not reach more than 93.3 kPa (700 mmHg, 27.6 in.Hg) in 15 minutes, there is probably a leak in the system. Partially charge the system, and check for leaks.
SYSTEM CHARGING
Air conditioning refrigerant or lubricant vapor can irritate your eyes, nose, or throat.
Be careful when connecting service equipment.
Do not breathe refrigerant or vapor.
1.
Connect a R-134a refrigerant recover/recycling/charging station(A) to the high-pressure service port(B) and the low-pressure service port(C), as shown, following the equipment manufacture s instructions.

2.
Add the same amount of new refrigerant oil to the system that was removed during recovery. Use only FD46XG (PAG) refrigerant oil
3.
Carge the system with the specified amount of R-134a refrigerant. Do not overcharge the system; the compressor will be damaged.

Refrigerant capacity : 600 ± 25g