Chrysler PT Cruiser. Manual - part 971
Condition
Possible Causes
Correction
The low side pressure is too
high, and the high side
pressure is too low.
1. Accessory drive belt
slipping.
1. Inspect the accessory drive belt condition and
tension. Tighten or replace the accessory drive
belt, if required. Refer to Group 7.
2. Faulty A/C variable orifice
tube.
2. See A/C Variable Orifice Tube in this group.
Replace if required.
3. Faulty A/C compressor.
3. See A/C Compressor in this group. Replace
the compressor, if required.
The low side pressure is too
low, and the high side
pressure is too high.
1. Restricted refrigerant flow
through the refrigerant lines.
1. See Liquid Line, Suction Line and Discharge
Line in this group. Inspect the refrigerant lines for
kinks, tight bends or improper routing. Correct
the routing or replace the refrigerant line, if
required.
2. Restricted refrigerant flow
through the A/C variable
orifice tube.
2. See A/C Variable Orifice Tube in this group.
Replace if required.
3. Restricted refrigerant flow
through the A/C condenser.
3. See A/C Condenser in this group. Replace the
restricted condenser, if required.
HEATER PERFORMANCE
WARNING: Review safety precautions and warnings
in this group before performing this procedure
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNINGS) and (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAUTIONS).
Failure to follow the warnings and cautions could
result in possible personal injury or death.
Check the coolant level, drive belt tension, radiator
air flow and fan operation. Start engine and allow to
warm up to normal operating temperature.
WARNING: Do not remove radiator cap when engine
is hot, personal injury can result.
If vehicle has been run recently, wait 15 minutes
before removing the radiator cap. Place a rag over
the cap and turn it to the first safety stop. Allow
pressure to escape through the overflow tube. When
the system pressure stabilizes, remove the cap com-
pletely.
MAXIMUM HEATER OUTPUT: TEST AND ACTION
Engine coolant is provided to the heater system by
two heater hoses. With the engine idling at normal
operating temperature, set the temperature control
to maximum heat, the mode control to the floor posi-
tion, and the blower in the highest speed position.
Using a test thermometer, check the temperature of
the air being discharged from the floor outlets. Com-
pare the test thermometer reading to the Heater
Temperature Reference chart.
HEATER TEMPERATURE REFERENCE
Ambient Temperature
Minimum Floor Outlet
Temperature
Celsius
Fahrenheit
Celsius
Fahrenheit
15.5°
60°
62.2°
144°
21.1°
70°
63.8°
147°
26.6°
80°
65.5°
150°
32.2°
90°
67.2°
153°
If the floor outlet air temperature is insufficient,
refer to 7 - COOLING - DIAGNOSIS AND TESTING.
Both heater hoses should be HOT to the touch (cool-
ant return hose should be slightly cooler than the
supply hose). If coolant return hose is much cooler
than the supply hose, locate and repair engine cool-
ant flow obstruction in heater system.
OBSTRUCTED COOLANT FLOW Possible locations or causes
of obstructed coolant flow are as follows:
• Pinched or kinked heater hoses.
• Improper heater hose routing.
• Plugged heater hoses or supply and return ports
at the cooling system connections.
• Plugged heater core.
• Air locked heater core.
If proper coolant flow through the cooling system is
verified, and heater outlet air temperature is insuffi-
cient, a mechanical problem may exist.
MECHANICAL PROBLEMS
Possible causes of insufficient heat due to mechan-
ical problems are as follows:
• Faulty engine thermostat.
24 - 6
HEATING & AIR CONDITIONING
PT
HEATING & AIR CONDITIONING (Continued)