1983 300TDt (converted to R-134a) Why does it take such a long time for the A/C to begin to blow cool? The compressor seems to engage right away, but the fan will wait 10 minutes or more to start blowing low and several more minutes to blow higher even when selected on high. After it begins to cool it works fine until the engine is switched off for a minute (fuel stop), and then it's another 10 minutes or more of high desert heat. This problem seems to have been slowly developing over the past couple of months.