A/C PERFORMANCE CHECK FUNCTIONING PER DESIGN INTENT

1988 CUTLASS SUPREME MODELS/YEARS: (TO DETERMINE IF CAR IS FUNCTIONING PER DESIGN INTENT)

To evaluate customer comments of reduced A/C performance, use the following procedure and upper limit performance data to determine if the air conditioning system is functioning per design intent on 1988 Cutlass Supremes.

TEST PROCEDURE

1. Park vehicle inside or in shade. 2. Open windows to ventilate interior. 3. Vent engine exhaust. 4. Install high and low side pressure gages. Route lines over rear hood seal and tape gages to windshield for viewing by driver. 5. Close hood. 6. Record ambient temperature at vehicle. 7. Record relative humidity. Use psychrometer or consult local weather bureau. 8. Close doors and windows. 9. Set air conditioning controls: Outside Air ("Norm") High Blower Full Cold 10. Open A/C outlets. 11. Place thermometer in right center A/C outlet. 12. Place transmission in park or neutral, start engine, stabilize at 2000 rpm and start timer. 13. Run until outlet air temperature reaches lowest temperature (about 3 minutes). 14. Record outlet air temperature and high side and low side pressures 15. Compare readings with upper limit data in attached chart. Normally operating vehicle should not exceed levels shown. If values are exceeded, proceed as shown below.

Note the effect of relative humidity and ambient temperature on outlet temepratures. It is very important to record conditions at time of test.

OVERCHARGED A/C SYSTEM ---------------------- Refrigerant overcharge can be a contributing factor to the reduced performance of the A/C system.

If the A/C temperature and pressure readings are not within the limits shown on the performance chart, the system refrigerant charge should be suspect.

Discharge, evacuate and refill the system with 1.021 kg (2.25 lbs.) of refrigerant, per the label on the left front strut tower.

The A/C system should then be rechecked for performance.

If values on chart are still exceeded, proceed with diagnostic procedure in service manual.

REDUCED A/C PERFORMANCE AT IDLE OR LOW SPEEDS IN CITY TRAFFIC ------------------------------------------------------------- This condition may be caused by reduced air flow across the condenser due to the cooling fan not being on all the time. This can be addressed by disconnecting the electrical connector to the coolant fan A/C refrigerant (intermediate) pressure switch. This switch is located in the high pressure line from evaporator to condenser, as shown in Figure 1. Tape the connector back on the harness making sure that the tape seals the opening of the connector, do not remove or replace the switch. Disconnecting this switch will allow the coolant fan to run all the time when the A/C is on and improve the air flow across the condenser.

Labor Operation Number: D1130 Labor Time: .2 hrs.

DELAYED A/C COOLING AFTER ENGINE START UP ----------------------------------------- Some vehicles may exhibit a slow to stroke V5 compressor causing a delay in the cooling of the A/C system. This condition can be addressed by using the procedure in Dealer Technical Bulletin 88-T-09 for delay A/C cooling.

1988 CUTLASS SUPREME A/C PERFORMANCE CHART UPPER LIMIT (REPLACES CHART PAGE 1 B-6 IN 1988 CUTLASS SUPREME SERVICE MANUAL) ------------------------------------

Right Center Relative Ambient Outlet Air Low Side High Side Humidity Air Temp Temp Pressure Pressure % Deg.F C Deg. Deg.F C Deg. PSIG KPA PSIG KPA --------- ------------ ------------ ---------- ---------- 20 70 21 43 6 32 221 175 1207 80 27 44 7 32 221 225 1551 90 32 50 10 32 221 275 1896 100 38 51 11 33 228 275 1896 30 70 21 45 7 32 221 190 1310 80 27 47 8 32 221 235 1620 90 32 54 12 34 234 290 2000 100 38 57 14 38 262 310 2137 40 70 21 46 8 32 221 210 1448 80 27 50 10 32 221 255 1758 90 32 57 14 37 255 305 2103 100 38 63 17 44 303 345 2379 50 70 21 48 9 32 221 225 1551 80 27 53 12 34 234 270 1862 90 32 60 16 41 283 325 2241 100 38 69 21 49 338 380 2620 60 70 21 50 10 32 221 240 1655 80 27 56 13 37 255 290 2000 90 32 63 17 44 303 340 23" 100 38 75 24 55 379 395 2724 70 70 21 52 11 32 221 255 1758 80 27 59 15 40 276 305 2103 90 32 67 19 48 331 355 2448 80 70 21 53 12 36 248 270 1862 80 27 62 17 43 296 320 2206 90 32 70 21 52 356 370 2551 90 70 21 55 13 40 276 285 1965 80 27 65 18 47 324 335 2310

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.