I've not heard of the condensate drains becoming blocked on a 124 chassis car. There are two of them, they exit out the bottom of the HVAC box, they are large diameter, and proceed straight through the transmission tunnel without and turns. See the attached photo of my '87 TD wagon receiving a new evaporator. The holes through which the condensate drains exit are circled. For reference, the gold box just rearward of the holes (the airbag trigger) is directly below the radio.

At any rate, it's easy enough to check. Idle the car in place, windows open, on a humid day. You should accumulate two puddles of water under the car, one on either side of the transmission, just aft of the front wheels.

As for the cutting out after use, I suggest you check the clutch gap on the compressor. It should be 0.50mm +-.15mm. The gap increases over time as the clutch material wears. I find that once it reaches ~.80mm or so clutch engagement becomes inconsistent. And yes, one sign of excess clutch gap is when the compressor works fine from cold, but becomes sporadic after it warms up. Any decent auto a/c shop will have a kit with a selection of new spacers to reset the gap to spec.

Another possibility is the presence of grease/oil on the compressor clutch facing. This situation can cause enough slip when engaging the clutch that the safety cutout it triggered. Try cleaning the clutch facing using Simple Green, brake cleaner, etc.

Best of luck,

- JimY

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