Cooling Insufficient - Air Conditioning (A/C) System. Pontiac Montana 2000

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 2000 🢒 Montana 🢒 Engine 🢒 Engine Controls - 3.4L 🢒 Cooling Insufficient - Air Conditioning (A/C) System

Table 1:

A/C Performance Table

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

This step determines if there is enough refrigerant in the A/C system to operate it without damage.

This step is to determine if the A/C compressor is operating.

This step measures the performance of the A/C system.

This step is to allow for vehicle variations as well as high ambient temperatures.

Step

Action

Value(s)

Yes

DEFINITION: The following test measures the A/C system operating efficiency by comparing:

•	The ambient air temperature

•	The ambient air humidity

•	The pressure at the high-pressure side of the refrigeration system

•	The pressure at the low-pressure side of the refrigeration system

•	The temperature of the air being discharged into the passenger compartment

Park the vehicle inside or in the shade.
Open the windows in order to ventilate the interior of the vehicle.
If the engine is at operating temperature, allow the engine to cool.
Ensure that the ignition key is in the OFF position.
Install the J 39500-B .
Record readings of the low and high side STATIC pressures.

The low and high side pressure readings should be almost equal to each other once the system has come to rest.

Are both the low and high side pressures above the specified value ?

345 kPa (50 psi)

Go to Step 2

Go to Leak Testing

Start the vehicle.
Turn the A/C on.
Visually inspect under the hood to see if the A/C compressor clutch is engaged

Does the compressor clutch engage ?

Go to Step 3

Go to HVAC Compressor Clutch Does Not Disengage

Turn the engine OFF.

Important: Record the relative humidity and the ambient temperature AT THE TIME OF THE TEST.

Record the ambient temperature at the vehicle.
Record the relative humidity, using one of the following methods:

•	Use a psychrometer

•	Consult the local weather bureau

Close the vehicle doors and windows.
Open the driver's door window 5-6 inches.
Set the HVAC control assembly to the following positions:

•	The A/C on

•	The blower control to the highest position

•	The HVAC control assembly to discharge air through the I/P outlets

•	The temperature control to the coldest position

Install a thermometer in the I/P left center air outlet.
Install a thermometer in the I/P right center air outlet.
Apply the parking brake.
Place the transaxle/transmission in one of the following positions:

•

PARK

•

NEUTRAL

Start the engine and elevate the engine RPM to 2000 and maintain.
Operate the A/C system for 5 minutes.
Record the following information:

•	The outlet air temperature

•	The low-side pressure

•	The high-side pressure

Compare the low and high side pressures and the output temperature to the table below (LINK).

Does all the data recorded fall within the specified ranges of the table below?

Go to Step 9

Go to Step 4

If the pressures and temperatures recorded do not fall within the specified ranges:

Continue to operate the A/C system for an additional 5 minutes.
Record the pressures and temperatures again.
Compare the low and high side pressures and the output temperature to the table below.

Does all the data recorded fall within the specified ranges of the table below?

Go to Step 9

Go to Step 5

Compare the recorded pressures to the A/C System Pressure - Zone Classification Chart below.

Do both the low and high side pressures fall within Zone A on the chart ?

Go to Cooling Insufficient - Air Conditioning (A/C) System - Pressure Zone A

Go to Step 6

Do the pressures fall within Zone B ?

Go to Cooling Insufficient - Air Conditioning (A/C) System - Pressure Zone B

Go to Step 7

Do the pressures fall within Zone C ?

Go to Cooling Insufficient - Air Conditioning (A/C) System - Pressure Zone C

Go to Step 8

Do the pressures fall within Zone D ?

Go to Cooling Insufficient - Air Conditioning (A/C) System - Pressure Zone D

Go to Step 9

Operate the system in order to verify the repair.

Did you correct the condition ?

System OK

Go to Symptoms in HVAC System - Manual

A/C System Pressure -- Zone Classification

A/C Performance Table

Relative Humidity	Ambient Air Temperature		Low Side Pressure		Engine Speed	High Side Pressure		Center Air Outlet Temperature
	Ambient Air Temperature		Low Side Pressure			High Side Pressure		Front		Rear
	°C	°F	kPa	psi		kPa	psi	°C	°F	°C	°F
Important: Use this table in conjunction with the appropriate diagnostic tables.
20%	27	80	186-228¹	27-33¹	2000 RPM	1496-1538¹	217-223¹	10¹	50¹	11¹	51¹
	32	90	200-241	29-35		1703-1744	247-253	12	53	12	53
	38	100	241-283	35-41		2186-2227	317-323	14	58	16	60
30%	20	70	186-228¹	27-33¹	2000 RPM	1496-1538¹	217-223¹	10¹	50¹	11¹	51¹
	27	80	221-262	32-38		1772-1813	257-263	13	56	13	56
	32	90	241-238	35-41		2144-2186	311-317	15	59	16	60
	38	100	290-331	42-48		2496-2537	362-368	18	64	18	64
40%	21	70	186-228¹	27-33¹	2000 RPM	1496-1538¹	217-223¹	11¹	51¹	11	51
	27	80	248-290¹	36-42¹		2048-2089¹	297-303¹	15¹	59¹	15	59
	32	90	276-317	40-46		2427-2468	352-358	18	65	18	65
	38	100	338-379	49-55		2668-2710	387-393	22	72	22	72
50%	21	70	207-248¹	30-36¹	2000 RPM	1807-1848¹	262-268¹	13¹	55¹	13	55
	27	80	269-310	39-45		2193-2234	318-324	17	63	17	63
	32	90	290-331	42-48		2462-2503	357-363	21	70	21	70
	38	100	352-393	51-57		2703-2744	392-398	24	76	24	76
60%	21	70	221-262¹	32-38¹	2000 RPM	1875-1917¹	272-278¹	13¹	55¹	13	55
	27	80	269-310¹	39-45¹		2220-2262¹	322-328¹	16¹	60¹	16	60
	32	90	297-338	43-49		2462-2503	357-363	18	64	18	64
	38	100	359-400	52-58		2703-2744	392-398	22	71	23	73
70%	21	70	228-269¹	33-39¹	2000 RPM	1910-1951¹	277-283¹	11¹	51¹	11	51
	27	80	276-317¹	40-46¹		2324-2365¹	337-343¹	14¹	58¹	15	59
	32	90	310-352	45-51		2462-2503	357-363	18	65	19	67
	38	100	359-400	52-58		2737-2779	397-403	23	74	23	74
80%	21	70	290-331¹	42-48¹	2000 RPM	1944-1986¹	282-288¹	10¹	50¹	11	51
	27	80	310-352	45-51		2358-2400	342-348	13	56	14	58
	32	90	338	49		2462-2503	357-363	19	67	21	69
90%	21	70	241-283¹	35-41¹	2000 RPM	1979-2020¹	287-293¹	15¹	59¹	16	60
90%	27	80	317-359	46-52	2000 RPM	2393-2434	347-353	16	61	17	62
¹This data reflects the performance obtained while the engine cooling fans were operating in series (low speed), rather than in parallel (high speed).