I've found them acceptable with R-12 here in high temp, high humidity Virginia summers.

R-134a makes them marginal, even at best.

Some have installed larger condensors and had success.

Strangely, the A/C units in my W114/W115 cars were ice cold....

Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles