GM Service Manual Online
For 1990-2009 cars only

Due to its variable displacement feature, special caution is necessary when diagnosing insufficient cooling conditions with the V-5 compressor. It is normal for liquid refrigerant to collect in the compressor crankcase during extended periods of shutdown, therefore, cooling action may be delayed up to 2 minutes until the refrigerant is pumped from the compressor crankcase.

Perform the following procedure if there is a delay in cooling upon start-up beyond 2 minutes, and the normal service manual operating procedure for the A/C compressor clutch and the electrical engine cooling fan operation has been accomplished:

  1. Select the NORM A/C position.
  2. Select the high blower position.
  3. Ensure that the A/C compressor clutch is engaged.
  4. Ensure that the electrical engine is operating.
  5. Ensure that the A/C is operating.
  6. Idle the engine for 2 minutes.
  7. Perform the following procedure if there is no cooling:
  8. 7.1. Operate the engine at approximately 3,000 rotations per minute (RPM) for 1 minute.
    7.2. Ensure that the engine is idling.
    7.3. Select the mode control to the VENT position for 1 minute.
  9. Set the A/C system back to NORM A/C mode.
  10. Ensure that the A/C system is operating.
  11. Run the engine at approximately 3,000 RPM for 1 minute.
  12. Perform the following procedure if there is no cooling:
  13. 11.1. Ensure that the A/C system is operating.
    11.2. Drive the vehicle in a normal manner for 5 minutes.
    11.3. Inspect the A/C system for normal operation. If there is no cooling, refer to VDOT Air Conditioning (A/C) System Diagnosis .

R-134a Temperature-Pressure Chart

Temperature

Pressure

°C

°F

kPa

psi

-9

16

106

15

-8

18

115

17

-7

20

124

18

-6

22

134

19

-4

24

144

21

-3

26

155

22

-2

28

166

24

-1

30

177

26

0

32

188

27

1

34

200

29

2

36

212

31

3

38

225

33

4

40

238

35

7

45

272

40

10

50

310

45

13

55

350

51

16

60

392

57

18

65

438

64

21

70

487

71

24

75

540

78

27

80

609

88

30

85

655

95

32

90

718

104

35

95

786

114

38

100

857

124

39

102

887

129

40

104

917

133

41

106

948

137

42

108

980

142

43

110

1012

147

44

112

1045

152

46

114

1079

157

47

116

1114

162

48

118

1149

167

49

120

1185

172

50

122

1222

177

51

124

1260

183

52

126

1298

188

53

128

1337

194

54

130

1377

200

57

135

1481

215

60

140

1590

231

63

145

1704

247

66

150

1823

264

68

155

1948

283

71

160

2079

301

74

165

2215

321

77

170

2358

342

    • Evaporator temperature range is -7-10°C (20-50°F).
    • Evaporator pressure range is 124-310 kPa (18-45 psi).
    • Condenser temperature range is 42-74°C (108-165°F).
    • Condenser pressure range is 980-2215 kPa (142-321 psi).