1986 Oldsmobile Cutlass AC keeps cycling

Hi
What are running pressures low and high side? System converted to R134A? Is cycling switch ie. Low pres new?
Let me know
Thanks for donate

Hi willtbear,

Thank you for the donation.

Perform the following test and see if you can come up with anything.

REFRIGERANT SYSTEM DIAGNOSIS
INSUFFICIENT COOLING "QUICK-CHECK" PROCEDURE

This procedure may be used to determine whether or not the A/C system has the proper refrigerant charge. Ambient air temperature must be above 70 °F (21 °C). It can eliminate an entire system checkout.

1. Start engine and bring to normal operating temperature. Ensure engine is at normal idle speed. Open doors and engine hood (trunk on Fiero models). Set function lever to "NORM" position, temperature lever to "COLD" position, and blower on "HI" position.

2. "Hand-feel" the temperature of the accumulator surface AND the evaporator inlet pipe while the compressor is engaged. It is normal for the compressor to cycle on and off to meet system requirements. If the accumulator surface and evaporator inlet pipe are the same temperature, and slightly cooler than ambient air, system is normal.

3. If inlet pipe is frosted or feels cooler than accumulator surface, then add refrigerant in 4 oz. Increments, allowing system to stabilize between additions, until both feel same temperature. Add 14 oz. More refrigerant.

INSUFFICIENT COOLING "THOROUGH CHECK" PROCEDURE
NOTE:
CCOT system is not equipped with a sight glass, and under no circumstances should a sight glass be installed.

1. To thoroughly check refrigerant system, attach manifold gauge set, and refer to Insufficient Cooling Chart on the following pages. Note that compressor clutch cycles on and off during normal operation.

2. When using Insufficient Cooling Chart, note that minor variations occur in cycling pressures, but otherwise procedures apply to all models.

3. In checking cycling of clutch on various models, it may be necessary to connect a jumper wire to terminals and leads of various cut-off switches and relays in order to check system fully.

The Insufficient cooling chart has too small prints to be posted here so I will send them to you in pdf format.