[asphaltgambler]

I think that most here are over thinking a solution with-out finding more about the cause.

1) Identify whether the car was converted to R134 when the previous major A/C work was done. If it has therin lies part of the source of the issue; deviation from stock designed components. R134 is less efficient and runs significantly higher high side pressures than R12. If indeed it has been and all below items addressed a higher effficiency condenser may be needed.

2) Dirty / clogged condenser fins. You would be so suprised if you removed the grill for access to the condenser, then liberally applied a good cleaner like simple green then power wash and watch the debris hit the ground. What a huge difference it makes in the high side pressure

3) Clutch fan worn out. No airflow for sure will make this happen everytime. From your description of the cars condition and mileage sounds as replacement is no brainer.

4) System is slightly over charged. Pressure = heat. Depending on the vehicle it could be just slightly overcharged but the difference in cooling would be substantial to point of activating the high pressure cut-out switch (if equipped) to cut the compressor when pressures get too high.