weight CHEVROLET DYNASTY 1993 Workshop Manual

(1) Attach manifold gauge set.
(2) Open the windows of the passenger compart-
ment and set the air conditioning controls to A/C,
RECIRC, and Low blower speed. (3) Start the engine and allow it to warm up to
normal running temperature. (4) If the air conditioning compressor does not en-
gage, disconnect the low pressure cut-off switch.
Place a jumper wire across the terminals in the con-
nector boot. If the compressor still does not engage, a
problem exists in the compressor clutch feed circuit. (6) Hold the engine speed at 1400 rpm.
(7) Following the instructions provided with the
charging equipment being used. Charge through the
suction side of the system. Use enough refrigerant to
clear the sight glass in the filter drier. (8) At the point when the sight glass clears, note
the weight of the refrigerant supply drum or the
level in the charging cylinder. Then add an addi-
tional 340 g (12 oz) of refrigerant to the system. Re- move the jumper wire from the low pressure cut-off
switch connector and connect the cut-off switch.
(9) Test the over all performance of the air condi-
tioner as described in A/C Overall Performance Test
in this Group. Close all valves on the charging equip-
ment and disconnect the hoses from the service ports
as described in the Manifold Gauge Set Connections
section of this Group. Install the service port caps.
DISCHARGING REFRIGERANT SYSTEM
(R-12) refrigerant is a chlorofluorocarbon (CFC)
that can contribute to the depletion of the ozone
layer in the upper atmosphere. To help protect the
ozone layer, an R-12 refrigerant recycling device
must be used. Use this device when it is necessary to
empty the refrigerant system. Contact an automotive
service equipment supplier for refrigerant recycling
equipment. Refer to the operating instructions pro-
vided with the recycling equipment for proper opera-
tion.
EVACUATING REFRIGERANT SYSTEM
If the A/C system has been open to the atmosphere,
it must be evacuated before the system can be
charged. Moisture and air mixed with the refrigerant
will raise the compressor head pressure above accept-
able operating levels. This will reduce the perfor-
mance of the air conditioner and damage the
compressor. Moisture will boil at near room temper-
ature when exposed to vacuum. To evacuate the re-
frigerant system: (1) Connect a suitable charging station, refrigerant
recovery machine, and a manifold gauge set with
vacuum pump. (2) Open the suction and discharge valves and
start the vacuum pump. When the suction gauge
reads -88 kPa (-26 in. Hg) vacuum or greater, close
all valves and turn off vacuum pump. If the system
fails to reach specified vacuum, the refrigerant sys-
tem likely has a leak that must be corrected. If the
refrigerant system maintains specified vacuum for at
least 30 minutes, start the vacuum pump. Then open
the suction and discharge valves, and allow the sys-
tem to evacuate an additional 10 minutes. (3) Close all valves. Turn off and disconnect the
vacuum pump. The refrigerant system is prepared to be charged
with refrigerant.
CHARGING REFRIGERANT SYSTEMÐEMPTY
SYSTEM
CAUTION: Do not over charge refrigerant system,
as excessive compressor head pressure can cause
noise and system failure.
Fig. 6 Testing for A/C LeaksÐTypical Front/Rear A/C System
Ä HEATING AND AIR CONDITIONING 24 - 11

INTRODUCTION
CONTENTS
page page
BODY CODE PLATE LOCATION AND DECODING INFORMATION ........................ 2
INTERNATIONAL SYMBOLS ................ 9
METRIC SYSTEM ........................ 6
METRIC THREAD AND GRADE IDENTIFICATION ....................... 6 TORQUE REFERENCES
.................... 6
VEHICLE FAMILY IDENTIFICATION ........... 1
VEHICLE IDENTIFICATION NUMBER ......... 1
VEHICLE SAFETY CERTIFICATION LABEL ..... 1
VEHICLE FAMILY IDENTIFICATION
Throughout this service manual references are made
to Vehicle Family, Body Codes. The letters AA, AC, AG,
AJ, AP, or AY are body codes that are assigned to a
individual vehicle family (Fig. 1). Also digit boxes 34,
35 and 36 on the Body Code Plate indicate the Vehicle
family.
VEHICLE SAFETY CERTIFICATION LABEL
A vehicle safety certification label (Fig. 2) is attached
to the rear facing of the driver's door. This label
indicates date of manufacture (month and year), Gross
Vehicle Weight Rating (GVWR), Gross Axle Weight
Rating (GAWR) front, Gross Axle Weight Rating (GAWR) rear and the Vehicle Identification Number
(VIN). The Month, Day and Hour of manufacture is
also included. All communications or inquiries regarding the ve-
hicle should include the Month-Day-Hour and Vehicle
Identification Number.
VEHICLE IDENTIFICATION NUMBER
The Vehicle Identification Number (VIN) is located
on the upper left corner of the instrument panel, near
the left windshield pillar. The VIN consists of 17
characters in a combination of letters and numbers
that provide specific information about the vehicle
(Fig. 3). Refer to VIN Code Breakdown Chart.
Fig. 3 Vehicle Identification Number (VIN Plate)
Fig. 1 Vehicle Family Identification
Fig. 2 Vehicle Safety Certification Label
Ä INTRODUCTION1