Subject: | Loss of Airflow from A/C Outlets after Extended Periods of Highway Driving
(Adjust A/C Compressor Set Point) |
Models: | 1991-1993 Saturns equipped with air conditioning |
Condition
After extended periods of highway driving, some customers may notice a loss
of airflow from the A/C outlets.
Cause
A/C compressor suction set point may be set low from factory, resulting in evaporator
freeze after extended periods of highway driving.
Correction
Adjust A/C compressor set point using the following procedure:
- Remove service port caps from discharge and suction
valves and reclaim, evacuate and recharge the system with 1.02 kg (2.25 lb)
of R-12.
- Install manifold gage set.
Important: To ensure accuracy, make sure gages have been calibrated.
- Start engine and allow it to fully warm-up to operating temperature (approximately
three-to-five minutes).
- Install portable diagnostic tool (PDT) to data link connector (DLC).
- Using PDT "Special Test/Idle Control," maintain engine speed
at 2000 RPM.
- Make sure RECIRC (inside airflow) is activated and hold discharge (high-side)
pressure at 1380 kPa (200 psi) by adjusting the mode, temperature and
blower fan speeds.
- If suction (low-side) pressure is below 183 kPa (26.5 psi)
when discharge pressure is at 1380 kPa (200 psi), proceed to next step.
If suction (low-side) pressure is not
below 183 kPa
(26.5 psi) , refer to "1991-1994 HVAC Service Manual" for
further diagnostics.
Caution: Do not turn the set screw on the back of the compressor counterclockwise. The
A/C system is under pressure and turning the set screw counterclockwise could cause
the set screw and/or a hot refrigerant/oil mixture to be discharged under pressure,
causing burns and/or bodily injury.
- Using a standard screwdriver, adjust A/C compressor
set point by turning set screw, in increments of 1/8 of a turn, clockwise
until suction (low-side) pressure gage reads 183 kPa (26.5 psi).
The A/C compressor set screw is located at the rear of the A/C compressor, underneath
a nickel-sized silver sticker. (The screwdriver can be easily inserted through the
sticker.)
Important: It is very important that the discharge (high-side) pressure be held at 1380 kPa
(200 psi) for five minutes after A/C compressor set screw adjustment. This
allows the A/C system to stabilize and to ensure the proper setting has been obtained.
- After system has been stabilized and set screw adjustment has been verified
to be correct, remove manifold gage set and PDT.
- Install service port caps on discharge and suction valves.
Claim Information
To receive credit for this repair during the warranty coverage period, submit
a claim through the Saturn Dealer System as follows:
Case Type
| Description
| Labor Operation Code
| Time
|
VW
| Reclaim, Evacuate, Recharge, A/C System and Adjust A/C Compressor Set Point
| T9693
| 1.3 hrs
|