I have no problem with A/C cooling in my 95, the only time it started to act like this was when the Aux fans resistor burned up and even took out the slow speed part of the circuit (although intermittently).

as leathermang said - first a gauge hookup can tell you lots of information within an A/C unit - then do a test, when the car is running with A/C at load and engine hot, rev it up - does the engine fan roar?

then do another test, reverse the car for a few feet, does the air get warm? - if it does then your aux fans are probably not working when required. Even with them at low rpm they are enough to cool down the condenser.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)