cooling DODGE RAM 1999 Service User Guide

from housing. To install, reverse removal procedure. Install new "O"
rings to A/C fittings. Evacuate and charge A/C system.
Removal & Installation (Durango - Rear Evaporator Core)
1) Disconnect negative battery cable. Discharge A/C system,
using approved refrigerant recovery/recycling equipment. Remove
headliner from passenger compartment of vehicle. Remove sun visors and
sun visor arm supports.
2) Remove coat hooks, overhead assist handle and dome light.
If equipped, remove overhead console. Remove air outlet bezel from
rear A/C-heater assembly. Remove rear blower motor switch. Remove
upper liftgate opening trim. Disengage "A", "B", "C", and "D" pillar
trim as necessary to prevent trim panel interference.
3) Move second and third row seats to cargo position. Move
front seats to full recline position. Remove headliner fasteners.
Carefully bow headliner and remove through lift gate opening.
4) Disconnect "B" pillar drain hoses from "Y" fittings.
Disconnect "B" pillar refrigerant lines and plug or cover all openings
in A/C system. Remove lower A/C-heater assembly cover. Remove screws
securing refrigerant tube and retaining strap to right side of upper
housing cover. Remove evaporator core. To install, reverse removal
procedure. Install new "O" rings to A/C fittings. Evacuate and charge
A/C system.
Removal & Installation (Ram Pickup - Front)
1) Remove and disassemble A/C-heater housing. See
A/C-HEATER ASSEMBLY . Separate halves of A/C-heater housing and remove
top half. Remove evaporator or heater core from housing.
2) To install, reverse removal procedure. Install new "O"
rings to A/C fittings. Evacuate and charge A/C system. Fill cooling
system. On 5.9L diesel engine, engine is equipped with a one-way check
valve. DO NOT run engine while filling cooling system. Fill engine
with engine turned off.
INSTRUMENT PANEL
Removal & Installation (Dakota & Durango)
1) Disconnect negative battery cable. Disable air bag system.
See AIR BAG SYSTEM SAFETY article. Place front wheels in straight-
ahead position. Remove sill trim from both doorways. Remove kick panel
covers from both sides of vehicle. Remove mounting screws for hood
release handle.
2) Remove steering column trim panel and support bracket.
Remove tilt steering column lever (if equipped). Remove upper and
lower shrouds from steering column. Unplug driver's side air bag
module. Loosen multifunction switch wiring harness connector screw and
disconnect from switch. Screw will remain in connector.
3) Disconnect PRNDL cable. Disconnect shift cable from
steering column. Remove steering coupler lock pin. Remove toe plate
retaining screws. Remove steering column mounting bolts and remove
steering column from vehicle.
4) Remove screw from bulkhead wiring harness connector and
disconnect. Disconnect 2 body wiring harness connectors located next
to bulkhead connector. Disconnect 3 wiring harness connectors, from
junction block, located nearest to dash panel. Disconnect brake light
switch connector. Disconnect Rear Wheel Anti-Lock (RWAL) brake module
(if equipped), located near steering column support brackets.
5) Disconnect plastic retainer clip from parking brake
linkage rod, located at back of parking brake release handle. Remove
rod end from parking brake handle. Remove instrument panel center
support bracket. Unplug vacuum harness connector located at left end
of A/C-heater housing. Disconnect Air Bag Control Module (ACM)
connector.

6) Remove glove box. Reach through glove box opening and
disconnect antenna coaxial cable connector. Disconnect blower motor
connector located above glove box opening, near support brace for A/C-
heater housing. Disconnect radio ground strap. Loosen instrument panel
roll down bracket bolts about 2 turns, located at lower corners on
both sides of instrument panel. Remove 5 screws across top of dash
panel at base of windshield, removing center screw last.
7) Roll down instrument panel and install a temporary support
hook that is about 18" (457 mm) in length. Install hook from center
hole in instrument panel to center hole of dash panel. Pull lower
instrument panel outward until both roll down bracket bolts are in
slotted roll down position. Instrument panel should now be supported
and away from firewall.
8) Disconnect 2 door harness connectors, located on a bracket
near right end of instrument panel. Disconnect blower motor resistor.
Disconnect temperature control cable from A/C-heater housing and
remove from housing. See Fig. 5. Disconnect demister duct flexible
hose from A/C-heater housing.
9) Ensure instrument panel is free and clear for removal.
With the aid of an assistant, remove temporary support hook. Lift
instrument panel off of roll down bracket bolts and remove from
vehicle.
10) To install, reverse removal procedure. Ensure all wiring
and hoses are clear and not pinched. Tighten bolts and nuts to
specification. See TORQUE SPECIFICATIONS . Enable air bag system. See
AIR BAG SYSTEM SAFETY article.
Removal & Installation (Ram Pickup)
1) Disable air bag system. See AIR BAG SYSTEM SAFETY article.
Disconnect negative battery cable. Drain cooling system. Remove left
and right kick panel trim. Remove 5 screws and knee bolster/steering
column cover. Remove hood release and parking brake release handle
screws from lower instrument panel support. Remove 6 screws and
instrument panel support. Disconnect air bag connector at lower left
corner of instrument panel.
2) Pull PRNDL cable and twist to remove from position arm.
Push tab on bottom of cable retainer upward, then squeeze sides to
remove retainer from column. Remove tilt lever (tilt column only).
Remove both upper and lower shrouds from column. Remove lower fixed
column shroud. Loosen multifunction switch connector screw. Screw will
remain in connector.
3) Remove remaining steering column electrical connectors.
Remove air bag wiring harness from steering column wiring trough.
Remove wiring trough from steering column. Remove 3 toe plate nuts and
washers.
4) Remove 2 nuts and washers attaching steering column
bracket to instrument panel steering column support bracket. Allow
column to lower and rest on seat. Remove 2 screws from bottom of Air
Bag Control Module (ACM) cover. Remove 4 screws holding ACM to
transmission tunnel.
5) Disconnect wiring at ACM. Disconnect instrument panel left
side wiring connectors. Remove screw holding brake release to bottom
of instrument panel. Disconnect instrument panel right side wiring
connectors, which includes 2 connectors attached to A/C-heater
assembly housing, courtesy light connector, antenna cable and 2 body
connectors. Disconnect vacuum harness from A/C-heater system.
6) Remove 5 screws holding instrument panel to dash. Loosen
lower instrument panel pivot bolts. Roll instrument panel downward.
Remove instrument panel from vehicle.
7) To install, reverse removal procedure. Ensure all wiring
and hoses are clear and not pinched. Tighten bolts and nuts to
specification. See TORQUE SPECIFICATIONS . Enable air bag system. See
AIR BAG SYSTEM SAFETY article.

HIGH
Some possible causes of low side system pressure being high-
to-normal and high side system pressure being too high include:
* Condenser air flow restricted.
* Inoperative cooling fan.
* Faulty expansion valve.
* Refrigerant system overcharged.
* Air in refrigerant system.
* Engine overheating.
LOW SIDE PRESSURE IS HIGH & HIGH SIDE PRESSURE IS LOW
Some possible causes of low side system pressure being too
high and high side system pressure being too low include:
* Compressor belt is slipping.
* Fixed orifice tube not installed.
* Faulty compressor.
LOW SIDE PRESSURE IS LOW & HIGH SIDE PRESSURE IS HIGH
Some possible causes of low side system pressure being too
low and high side system pressure being too high include:
* Restricted refrigerant flow through refrigerant lines.
* Restricted refrigerant flow through expansion valve.
* Restricted refrigerant flow through fixed orifice tube.
* Restricted refrigerant flow through receiver-drier.
* Restricted refrigerant flow through condenser.
BLOWER MOTOR DIAGNOSIS
BLOWER MOTOR INOPERATIVE
Some possible causes of an inoperative blower motor include:
* Faulty fuse.
* Faulty blower motor feed circuit wire harness or
connectors.
* Faulty blower motor ground circuit wire harness or
connector.
* Faulty blower motor resistor.
* Faulty blower motor relay.
* Faulty blower motor switch.
* Faulty A/C-heater mode control switch.
* Faulty blower motor.
BLOWER NOT OPERATING IN ALL SPEEDS
Possible causes of the blower not operating in all speeds
include:
* Faulty fuse.
* Faulty blower motor feed circuit wire harness or
connectors.
* Faulty blower motor relay.
* Faulty blower motor resistor.
* Faulty blower motor switch.

2) Ensure service hoses are equipped with valve core
depressor to match Schrader valve. If not, install special adapters
for this purpose. If the high-side service hose connector will not fit
on high-side Schrader valve, a special adapter must be used. See
SPECIAL VALVE CONNECTORS.
3) Ensure both manifold gauge set hand valves are closed.
Connect low-side service hose to low-side (suction) service valve, and\
finger tighten connections. Connect high-side service hose to high-
side (discharge) service valve, and finger-tighten connections.
NOTE: After test gauges are installed, test hoses must be purged of
all air before proceeding with testing.
PURGING TEST HOSES
1) Ensure high-side and low-side hoses are properly connected
to service valves, and all hose connections are tight. Place a clean
shop towel over end of center service hose.
2) Purge high-side test hose by opening hand valve on high-
side gauge for 3-5 seconds. This allows the system's refrigerant to
force air through test hoses and out of center service hose into the
shop towel. Immediately close high-side gauge hand valve.
3) Purge low-side test hose in the same manner using hand
valve of low-side gauge. Close hand valve after 3-5 seconds. Purging
of test hoses is now complete, and system is ready for testing.
NOTE: If manifold gauge set is to be used in conjunction with
refrigerant recovery/recycling equipment, use instructions
provided with the recovery/recycling equipment to properly
purge test hoses.
STABILIZING A/C SYSTEM
1) Once manifold gauge set is attached to system and test
hoses have been purged, the system is ready for testing. Place all
test hoses, gauge set and other equipment away from all moving parts
of engine.
2) Start engine, and turn A/C controls to maximum cooling
position (full cold or MAX A/C). Set blower on high speed. Open doors
and/or windows. Operate system for 5-10 minutes. System should now be
stabilized and ready for test readings.
PRESSURE-TEMPERATURE RELATIONSHIP
A refrigerant, when confined in an enclosed space, increases
in pressure as the temperature increases. Conversely, if the
temperature is lowered, the pressure also decreases.
Depending on temperature, a corresponding pressure will exist
in such an enclosed space. For example, at 70
F (21.1C) a gauge will
indicate about 71.0 psi (5.0 kg/cm). The R-134a PRESSURE- TEMPERATURE
RELATIONSHIP table shows this relationship.
R-134a PRESSURE-TEMPERATURE RELATIONSHIP









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Temperature F (C) ( 1) psi (kg/cm)
20 (-6.7) ................................................. 18 (1.3\
)
30 (-1.1) ................................................. 26 (1.8\
)
40 (4.4) .................................................. 35 (2.5\
)
50 (10.0) ................................................. 45 (3.2\
)
60 (15.6) ................................................. 57 (4.0\
)

Fig. 14: Insufficient Cooling Of Condenser Or R-134a Refrigerant
Overcharge

1) Manufacturer recommends flushing contaminated system using
one gallon of Ford A/C System Flushing Solvent (F4AZ-19579-A), a
Filter (FL-1A), an A/C Flusher Fitting Kit (014-00992). DO NOT reuse\
flushing solvent and filter, they are intended to be used on one
vehicle only.
2) Discharge A/C system, using approved refrigerant
recovery/recycling equipment. Flush specified A/C components using A/C
System Flusher (014-00991), according to manufacturer's operating
instructions.
3) If an A/C system flusher is not available to clean A/C
system, an in-line filter kit can be used. Filter kit is installed
before replacement compressor, accumulator/receiver-drier, muffler,
and thermal expansion valve/fixed orifice tube have been installed.
4) Filter kits are used with either a rubber lined suction
hose or with a nylon lined suction hose located between compressor and
evaporator. Rubber lined hose has a wall thickness of 1/4" and nylon
lined hose has a wall thickness of 1/8". See Fig. 22.
5) The filter kit for either type hose has 2 filters. A
temporary pancake filter and a permanent in-line suction filter.
Pancake filter is temporarily installed between condenser and
condenser-to-evaporator line. See Fig. 23. Permanent filter is
installed in suction line between accumulator and compressor.
6) Install replacement components (compressor, accumulator
and fixed orifice) with correct amount of refrigerant oil. See
COMPRESSOR REFRIGERANT OIL CHECKING article.
7) Cut suction hose between compressor and accumulator
(closer to compressor). Remove a length of suction hose to accommodate\
suction filter. Measure side wall of suction hose and install
appropriate filter with "O" rings and filter clamps. If side wall is
1/4", use in-line filter labeled USE WITH RUBBER INNER LINED HOSE. If
side wall is 1/8", use in-line filter labeled USE WITH NYLON INNER
LINED HOSE. Ensure arrow on filter is pointing in direction of
refrigerant flow. Tighten hose clamps to 54 INCH lbs. (6 N.m). See
Fig. 22 .
8) Install pancake filter in liquid line between condenser
and condenser-to-evaporator line. Ensure filter inlet (label) is
toward condenser. Evacuate, charge, and leak test A/C system. See
EVACUATING A/C SYSTEM, CHARGING A/C SYSTEM and LEAK TESTING. Check
filters and hoses for clearance from other engine components. Use tie
straps if necessary.
9) Place an external cooling fan in front of radiator. Select
MAX A/C operation and set blower motor speed to maximum. Start engine
and allow to idle. Ensure A/C is operating properly. Slowly increase
engine speed to 800 RPM, then 1000 RPM, and then to 1200 RPM. With
engine speed set to 1200 RPM, operate engine for one hour with A/C
system operating.
10) Stop engine. Discharge A/C system, using approved
refrigerant recovery/recycling equipment. Remove pancake filter, hoses
and fittings. Discard pancake filter. Reconnect liquid line, evacuate,
charge, and leak test A/C system. Ensure A/C system is operating
properly.

vacuum reading of 26 in. Hg or more. Close all valves and turn vacuum
pump off. Observe vacuum gauge, go to next step.
2) If A/C system maintains specified vacuum for 5 minutes,
open low-side and high-side valves, restart vacuum pump and operate
for an additional 10 minutes. Close all valves. Turn vacuum pump off
and disconnect pump.
3) If A/C system cannot get to or maintain specified vacuum,
check for a defective vacuum pump or leak in A/C system or gauge set.
See LEAK TESTING. Repair or replace components as necessary.
CHARGING A/C SYSTEM
* PLEASE READ THIS FIRST *
CAUTION: During charging of A/C system, refrigerant container must be
in an upright position. If refrigerant container is
upside down, compressor may be damaged by liquid refrigerant
drawn into A/C system.
CHRYSLER CORP.
Avenger 2.0L & Sebring Coupe 2.0L
1) Ensure A/C system has no leaks and has been evacuated. See
EVACUATING A/C SYSTEM and LEAK TESTING. Locate sight glass on
receiver-drier and ensure it is clean. Close low-pressure adapter
valve and remove from manifold gauge set.
2) Connect low-pressure adapter valve to refrigerant
container and open container valve. Ensure Blue charging hose is
properly connected to vehicle low-pressure service valve. Open adapter
valve.
3) If refrigerant is not drawn in, fully close adapter valve
and check for hose connection leaks. If leak is detected, retighten
connections and repeat A/C system evacuation. See EVACUATING A/C
SYSTEM.
4) If refrigerant is drawn in, start engine. Turn A/C on and
set temperature control to maximum cold and blower motor to low speed.
Operate engine at 1500 RPM. As refrigerant is drawn into system, foam
or bubbles will appear in sight glass.
5) System charge will be close to full when sight glass is
clear, compressor clutch is engaged, and compressor suction and
discharge line temperatures are similar. System charge will be
complete when sight glass is clear, compressor clutch is engaged,
compressor discharge line is warm and suction line is cool.
6) When proper amount of refrigerant has been added, stop
engine. Close refrigerant container and adapter valve, and disconnect
gauge set.
Breeze, Cirrus, Concorde, Intrepid, LHS, Stratus & 300M (Scan
Tool Method)
1) Attach Diagnostic Readout Box (DRB) to Data Link Connecto\
r
(DLC). Set DRB (scan tool) to PARTIAL CHARGE TEST. Attach clamp-on
Thermocouple (80PK-1A) to liquid line, as close to condenser outlet as\
possible.
2) Set parking brake, and place transaxle in Park position.
Start engine and allow to idle. Set A/C controls to outside air, panel
mode, full cool, and high blower speed. Turn A/C on, and open vehicle
windows. Operate A/C system for a few minutes to allow system to
stabilize.
3) Place cardboard over front grille area, to block airflow
through part of condenser, to set A/C system pressure to 260 psi (18.3
kg/cm
). This will stop cooling fans from alternating speeds and
maintain constant pressure.

4) Scan tool will automatically calculate system charge.
Depending on system charge condition, corrections are made 2 ounces at
a time. Each time a correction is made, recheck readings to ensure
proper charge. For system refrigerant capacity, see REFRIGERANT OIL &
REFRIGERANT SPECIFICATIONS article.
Breeze, Cirrus, Concorde, Intrepid, LHS, Stratus & 300M
(Manifold Gauge Set Method)
1) Attach clamp-on Thermocouple (80PK-1A) to liquid line, as\
close to condenser outlet as possible. Attach manifold gauge set to
vehicle.
2) Set parking brake, and place transaxle in Park position.
Start engine and allow to idle. Set A/C controls to outside air, panel
mode, full cool, and high blower speed. Turn A/C on, and open windows.
Operate system for a few minutes to allow system to stabilize.
3) Place cardboard over front grille area, to block airflow
through part of condenser, to set A/C pressure to 260 psi (18.3
kg/cm
). This will stop cooling fans from alternating speeds and
maintain constant pressure.
4) Record temperature reading at liquid line and discharge
pressure reading on gauges. Compare readings with values in
REFRIGERANT CHARGE LEVEL table.
5) Depending on system charge condition, corrections are made
2 ounces at a time. Each time a correction is made, recheck readings
to ensure proper charge. For system refrigerant capacity, see
REFRIGERANT OIL & REFRIGERANT SPECIFICATIONS article.
REFRIGERANT CHARGE LEVEL









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Liquid Line Temp. ( 1) Discharge PressureF (C) psi (kg/cm)
40 (4.4) ........................................... 53-75 (3.7-5.3\
)
60 (15.6) ......................................... 81-104 (5.7-7.3\
)
80 (26.7) ....................................... 111-142 (7.8-10.0\
)
100 (37.8) ..................................... 156-194 (11.0-13.6\
)
120 (48.9) ..................................... 208-259 (14.6-18.2\
)
140 (60.0) ..................................... 272-331 (19.1-23.3\
)
160 (71.1) ..................................... 353-420 (24.8-29.5\
)
180 (82.2) ..................................... 447-516 (31.4-36.3\
)
( 1) - When pressure is lower than specified, system is undercharged.
When pressure is higher than specified, system is overcharged.









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All Other Models
Ensure A/C system has been checked for leaks and evacuated.
See EVACUATING A/C SYSTEM and LEAK TESTING. Charge A/C system to
specifications. For system refrigerant capacity, see REFRIGERANT OIL &
REFRIGERANT SPECIFICATIONS article.
FORD MOTOR CO.
1) If using approved Recovery/Recycling/Charging Center (023-\
00105 or 023-00150), connect to high-side and low-side service valves.
See SERVICE VALVE LOCATIONS under SYSTEM SERVICE VALVES. Operate
charging center according to manufacturer's instructions. Charge
system with specified amount of refrigerant and refrigerant oil. See
REFRIGERANT OIL & REFRIGERANT SPECIFICATIONS article. Check amount of
refrigerant oil in system before adding oil. See COMPRESSOR
REFRIGERANT OIL CHECKING article.
2) If using manifold gauge set, connect to high-side and low-
side service valves. See SERVICE VALVE LOCATIONS under SYSTEM SERVICE

VALVES. Connect 2 hoses with shutoff valves to manifold gauge set
center port. Connect one hose to vacuum pump and other hose to
refrigerant container. Weight of refrigerant container before and
after charging can be used to determine amount of refrigerant drawn
into system. Using vacuum pump, purge air from center hoses.
3) Fully open manifold gauge set low-side valve and
refrigerant container valve to allow refrigerant to enter A/C system.
When no more refrigerant is being drawn into A/C system, start engine
and allow to idle. Select MAX A/C, set blower motor speed to maximum
and allow remaining refrigerant to be drawn into A/C system.
NOTE: When ambient air temperature is high, it may be necessary to
use an external cooling fan to blow air through condenser and
radiator.
4) When proper amount of refrigerant has been added, close
refrigerant container valve. Allow any refrigerant remaining in hose
to be drawn into A/C system. When low-side pressure decreases to about
30 psi (2.1 kg/cm
), close center valve on manifold gauge set. Ensure
A/C system is operating properly. Disconnect manifold gauge set.
Install service port caps. Check system for leaks. See LEAK TESTING.
GENERAL MOTORS
Manufacturer recommends using A/C Refrigerant Recovery,
Recycling And Recharging (ACR4) System (J-39500). The ACR4 system ha\
s
one filtering cycle during recovery plus an automatic multiple pass
filtering during evacuation cycle. Follow manufacturer's instructions
provided with ACR4 equipment being used.
JEEP
Connect recovery/recycling equipment, meeting SAE standard
J1991 or J2210, to vehicle. Charge A/C system to specifications, using
equipment manufacturer's instructions.
LEAK TESTING
TYPES OF LEAK DETECTORS
Bubble Solution Detector
This is a solution applied externally at suspected leak
points. Leaking refrigerant will cause the detector to form bubbles
and foam. A soap and water solution also works well.
Dye Solution
This is a colored solution that may be introduced into the
A/C system. The dye will show up and color components at leak points.
Some manufacturers offer refrigerant containing a Red dye. This dye-
containing refrigerant is installed by normal charging procedures.
Other dye solutions are visible with a Black light only.
Electronic Leak Detector
This instrument will draw in any leaking refrigerant through
a test probe, and then sound an audible signal or create a flashing
light if refrigerant is found. It is the most sensitive of the leak
detectors used. Leak detectors are sensitive to windshield washing
solutions, many solvents and cleaners, and some adhesives. Ensure
surfaces near test areas are clean and dry to prevent false signal or
detector damage. Liquids ingested into detector will damage detector.
See Fig. 24 .

be detected if leak testing is performed too quickly.
BUBBLE DETECTOR LEAK TESTING PROCEDURE
This leak detection method is recommended when it is
impossible or difficult to determine the exact location of the leak
using other methods. Although commercial bubble detectors are more
effective, household soap solutions may be used.
Using the dauber that comes with the commercial soap
solution, apply the solution to all joints, connections, fittings or
controls where a leak might be suspected. If high-suds household
solutions are used, apply them with a small brush. Wherever bubbles
form, leaks are present and must be repaired. check the entire system
as there may be more than one leak.
ELECTRONIC LEAK TESTING PROCEDURE
NOTE: Some electronic leak detectors will function on only R-12
systems or on only R-134a systems, and some will function on
both R-12 and R-134a systems. Familiarize yourself with the
tester being used and know what type of system you are leak
testing.
Electronic leak detectors should be used in well ventilated
areas. Avoid using them around explosive gases. Always follow
manufacturer's instructions for the specific tester being used. If
none are available, proceed as follows:
1) Turn all controls and detector sensitivity knob to OFF
position or zero setting. Connect leak detector to an approved source
of power. Turn switch ON, and allow unit to warm up for approximately
5 minutes.
2) Check operation of tester by positioning probe in a
reference source where refrigerant is known to be present in small
amounts. Adjust controls and sensitivity knob until detector reacts
properly. Move probe away from refrigerant source and the reaction
should stop. If it continues, adjust the sensitivity knob to a lower
setting.
3) When tester reacts properly, leak test air conditioning
system by moving probe UNDER all components, fittings and connections.
Keep the probe moving. To check evaporator insert probe into drain
tube opening or a heater duct. DO NOT allow probe to contact
refrigerant or refrigerant oil. When leaks are found, repair them as
necessary. Keep in mind that there may be more than one leak.
DYE SOLUTION LEAK TESTING PROCEDURES
CAUTION: Dye-charged refrigerant cans are available to be used as
internal leak detectors. The use of this type of solution may
void some manufacturer's warranties. Be sure to check with
the A/C system manufacturer concerning the use of dye-charged
leak detectors. Dyes which work in R-12 systems will not work
in R-134a systems.
The following procedure is for introducing a dye solution,
not dye-charged refrigerant, into A/C system.
1) Connect manifold gauge set to air conditioning system in a
normal manner. Remove center hose from manifold gauge set, and replace
it with a short piece (6" long) of 1/4" tubing using two 1/4" flare
nuts. Connect a container of dye solution to the tubing.
2) Connect one end of gauge set center hose to dye solution
container. Connect a container of refrigerant to the other end of the
hose. Operate engine at idle speed. Set the air conditioning system
for maximum cooling. Slowly open the low-side hand valve to allow the