24-12
HEATING
AND AIR
CONDITIONING
PERFORMANCE TEMPERATURE CHART
Garage
Ambient
Temperature
21
°C
(70°F) 26.5°C
(80°F) 32°C
(90°F) 3/.5°'J
(100T) 43°C
(110°F)
Discharge
Air Temperature
3-10°C
(38-50°F) 6-12°C
(42-54'F) 8-14°C
(46-58°F) 10-17°C
(50-62°F) 12-19°C
(54-66°F)
Compressor
Discharge Pressure
1344 a
1620 a
1861 kPag 2103 a 1379kPcg
2344 a
Compressor
Discharge Pressure
120 •
195 PS'9 160 .
235 PS'9 200 .
270 PS'9 240 .
305 PS'9 280 .
340 PS'9
Evaporator
Suction Pressure
124 kPag
207 a 138 kPag
241 J 269 kPag III kP°9
296 179 ,D
324 kPag
Evaporator
Suction Pressure
18 .
30 PS'9 20 .
35 pS'g 22
39 pS,g
25 .
43 pS'g 26 .
47 pS'9
J9124-97 pressure must drop to below -50 kPag (15 inch of vacu
um).
If the condition is not met the H-valve is stuck
open and should be replaced. Remove Liquid C02 and
watch evaporator suction pressure; it should increase to a minimum of 262 kPag (38 psig) and then stabilize to a
pressure of 172-240 kPag (25-35 psig). Any H-valve
which does not produce this response is stuck open and should be replaced.
(4) Connect A/C water valve vacuum hose (gray)
and set temperature control in cool position.
(5) Set engine speed at 1,000 RPM and blower on
HI.
The evaporator suction pressure should be in the
range of 138-207 kPag (20-30 psig). If compressor dis charge is higher than 1 656 kPag (240 psig), check
for restricted discharge line, radiator overheating, air in system or faulty viscous fan drive. If discharge
pressure is less than 966 kPag (140 psig), check com
pressor head gaskets and discharge reeds.
(6) Connect the electrical wires to the electronic
temperature cycling clutch switch.
VACUUM CONTROL SYSTEM ADJUSTMENTS
AND TESTS To keep the vacuum harness in place, common vi
nyl tape (sometimes called plastic tape of electri
cian's tape) cannot be used. It will cause the tube to
deteriorate directly under the tape, when high under
hood temperatures are involved. A compatible nylon type of tape such as MS CH69 (#281) or an equivalent must be used.
The test of the push button switch operation deter
mines whether or not the vacuum and electrical cir cuits are properly connected and the controls are
functioning properly. However, it is possible that this system operating perfectly at engine idle during high
manifold vacuum, may not function properly at high engine speeds. Before starting this test, stop engine and make certain the vacuum source hose at engine
intake manifold is tight on its connector.
EXPANSION (H) VALVE TEST
Test must be made at ambient temperature of
21°C-29°C (70°F-85°F).
After performing all previously mentioned tests,
conduct the H-valve test as follows:
(1) Operate the engine at 1,000 RPM with the win
dows closed. Set air conditioning controls for MAX
A/C,
high blower, temperature control lever in full
reheat position and cycling clutch switch electrically
bypassed. Disconnect and plug the water valve vac uum hose in the engine compartment. (2) Operate the system for at least 5 minutes in or
der to obtain partial stabilization and sufficient re
heat to load the system. Pressure at the discharge service port should reach 966-1 656 kPag (140-240
psig) (Fig. 6). If head pressure of 966-1 656 kPag (140-240 psig) cannot be obtained, check system
charge level.
Fig.
6
Expansion
(H)
Valve
Test
WARNING:
EXTREME
CARE
MUST
BE
USED
WHEN
HANDLING
LIQUID
C02 AS
SKIN
INJURY
CAN OC
CUR
IF
PROTECTIVE
GLOVES
ARE NOT
WORN.
(3) Put Liquid C02 on control head (completely cover
head) for a minimum of 30 seconds. Evaporator suction
•
HEATING
AND AIR
CONDITIONING
24 - 21 (a) Loosen both test hoses at the manifold gauge
set. Tighten the hoses as soon as the air is purged. (b) Loosen charging hose connection at manifold
gauge set. This will purge air from the charging
hose.
Tighten connection as soon as air is purged.
(9) With vehicle windows open and hood up, oper
ate engine at 1,300 RPM. (10) Place air conditioner control on A/C and place
the fan switch on high. (11) If necessary, block the condenser to maintain
a discharge pressure of 1 550-1 725 kPag (225-250
psig).
System must be charged through the evapora
tor suction service ports as follows:
(a) Slowly open the suction service gauge valve.
Meter flow of refrigerant by adjusting the suction service gauge valve so the pressure registered at
the suction service gauge does not exceed 345 kPag
COMPRESSOR
J
(50
psig). Keep refrigerant container upright.
(b) Add refrigerant gas until there is no foam visi
ble at the sight glass. As soon as all foam clears, note the weight registered on the refrigerant scale.
(c) Watch the refrigerant weighing scale and add
437 g (14 oz.) of refrigerant (equivalent to 1 can).
(d) Close the suction gauge valve.
CAUTION:
TOO
much
refrigerant
in the
system
can
cause
abnormally high discharge pressures. Care
must
be
used
so the
exact recommended amount
of
refrigerant
is
added
after
foam clears
in the
sight
glass.
(e) Close dispensing manifold valve. Remove test
hoses and adapters from the service ports of com
pressor and install protective caps at service ports.
RVICE (SD-709)
INDEX
page
Compressor
21
Compressor
Shaft Seal
.................... 25
The A/C system uses a 7 piston design Sanden SD-
709 compressor. Designated the SD-709, the compres
sor is mounted on the front right side of the engine
and is driven by a serpentine belt.
System lubrication is provided by 135cc ±15cc (4.6
cu. in. ±0.5 cu. in.) of 500 viscosity refrigerant oil.
The clutch used on the compressor consists of 3 ba
sic components:
(1) The pulley.
(2) The front plate. (3) The field coil.
The pulley and field coil are attached to the front
head of the compressor with snap rings. The hub is keyed to the compressor shaft and is retained on the
shaft with a self-locking nut. Special service tools are
required to remove and install the clutch plate on
the compressor shaft.
COMPRESSOR
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Disconnect the clutch lead wire.
(3) Remove the discharge and inlet (suction) ser
vice valves from the compressor. Plug or tape all the
openings.
(4) Refer to Group 7, Cooling System and remove
the drive belt(s). (5) Remove the bolts and lift the compressor from
the mounting bracket (Fig. 1).
page
Cylinder Head
/
Valve Plate
27
Magnetic
Clutch
22
Fig.
1
Compressor
Mounting
INSTALLATION
If a replacement compressor is being installed,
check the oil level. Add or subtract oil as necessary.
Install the magnetic clutch on the compressor.
(1) Install the compressor on the mounting bracket.
Tighten the bolts to 27 N*m (20 ft. lbs.) torque.
(2) Refer to Group 7, Cooling System and install
the drive belt(s).
(3) Check the belt tension.
@ New drive belt-800-900 N (180-200 lbs-f).
• Used belt-623-712 N (140-160 lbs-f).
