Perform Ance D A T A; Checking O Il - Chevrolet 1977 light duty truck Service Manual

5. T E M P control set at " C O L D "
c on ditioning outlets open.
6. G a u g e set installed.
7. System settled out (run-in approxim ately
minutes).
8. A therm om eter placed in front o f vehicle grille
and ano th er in the right h a nd diffuser outlet.
N OTE: On O verhead
therm o m eter in the rear unit center outlet.
9. An 18" fan placed in front of the vehicle and
blowing into the condenser.
N O TE : H igher tem peratures and pressures will
occur at higher am bien t temperatures. In areas o f
high humidity it is possible to have therm om eter
and gauge readings approach but not reach the
figures listed in the perform ance tables and still
have a satisfactory op eratin g unit. However, it is
im po rtan t to rem e m be r that low pressure has a
direct relationship to nozzle outlet temperature. If
pressure is too low, ice will gradually form on the
evaporato r fins, restricting
passenger area and resulting in insufficient or no
cooling.
P E R F O R M A N C E DATA
The following Perform ance D ata define normal
operation o f the system un der the above conditions.
Relative hum idity does not a p p e a r in the tables because
after ru n n in g the prescribed
recirculated air and m axim um
hum idity o f the air passing over the evaporator core will
re m ain at approximately 35% to 40% regardless o f the
a m b ien t tem perature or humidity.
C H E C K IN G OIL
In the six cylinder compressor it is not recom­
m ended that the oil be checked as a matter o f course.
Four-Season A ir Conditioning (C-K Models)
(R efrigerant Charge - 3 Lbs.
T em perature of
Air E ntering
70°
C ondenser
Engine rpm
Com pressor Head 150-
Pressure * 205
A ccum ulator
20-
Pressure * 26
Discharge Air
41-
Tem p, at Right
47
Hand O utlet *
and all air
Systems, place a third
air flow into
length o f time
cooling, the relative
- 1 2 o z . )
80° 90° 100° 110°
2000
170- 190- 220- 240-
220 290
240 270
20- 21- 22- 23-
28 29 30 32
41- 42- 43- 43-
47 50 51 51
Overhead System (C -K Models)
10
(R efrig e ra n t C harge - 5 lbs.-4 o z .)
T e m p e ra tu re of
A ir E n tering
C o n d en ser
E ngine rp m
C om pressor
H ead
P ressure *
A c c u m u la to r
Pressure *
D ischarge A ir
T em p , a t R ig h t
H and O u tle t *
R ear C en ter
O u tle t *
the
C 6 0 System (G Models)
(R efrig eran t Charge — 3 lb s .)
on
T e m p eratu re of
Air E ntering
C ondenser
Engine rp m
C om pressor
H ead Pressure*
Su ctio n
Pressure*
D ischarge Air
T em p, a t R ight
U pper O utlet*
Generally, compressor oil level should be checked only
where there is evidence o f a m ajor loss of system oil such
as might be caused by:
• A broken refrigerant hose
• A severe hose fitting leak
• A very badly leaking compressor seal
• Collision dam ag e to the system components
As a quick check on compressor oil charge, operate
the engine at
idle
10 minutes, turn off the engine and momentarily crack
open the oil drain plug on bottom of the compressor
letting a slight am ount o f oil d rain out. Retighten plug.
Again slightly crack open the plug. If oil comes out, the
compressor has the required am ount of oil.
70° 80° 90° 100°
2000
135- 160- 195- 230-
185 210 245 280
22- 22- 30- 33-
28 30 38 41
42- 42- 50- 54-
48 48 58 62
43- 47- 50- 55-
49 53 63
58
70° 80° 90° 100° 110°
2 0 0 0 RPM
10 20 1 4 0 - 1 6 0 -
1 9 0 -
60 70 190
210 240
3 - 3 -
3- 4 -
9 10 14
9 9
4 3 -
42 4 2 -
4 5 - 4 9 -
48 48 49 57 56
on maximum cold for approximately
110°
270-
320
37-
47
57-
67
58-
68
120°
2 1 0 -
2 6 0
7-
1 0 -
18
5 3 -
60