As the 100 degree days roll into Phoenix the need for a functional AC rises exponentially every day. Here is my issue:

My 1990 740 GL has an R12 system. When turned on, the air that it blows is the same temperature as the ambient air outside the car. No odd noises, squeals, etc are heard while the AC is engaged. The system blows stronger as you turn it up (and an accompnaying loss of power is felt in the drive of the vehicle), however the temperature of the AC air remains the same as outside.

I was thinking of having the R12>R134 conversion done but I don't want to jump into a $250 job done which does not result in a cooler cabin. Any thoughts/guidance on this issue would be greatly appreciated. Thanks!