Would compressed air hurt his brand new receiver drier?

At 90 deg F R134 should provide about 100 psi. You should hear the leak or see it with soap bubbles.

Thanks Kuehl.

I had some Nylog left over from a home mini-split ac installation, so figured I should use it.

The leak most likely is on the sections I worked on, which is the line along the left door sill to the condenser in the left fender (this is a 1995, so I don't have a deck lid condenser), and the drier, which is stuck in the back of the left front wheel well. It was very hard to get the connections made in there.

Assuming your compressor's tank is not filled with water at the bottom, common in this humidity, drain the air compressor tank before you start. Shop air or compressor air containing ambient humidity will not hurt the drier; as you are going to pull a proper evacuation after your done finding the leak. Whether you are going to hear or see R134a as a test medium .. reaching 100 psi is doubtful with a vacuum leak that flattens out at 5 inches of mercury. Use compressed air, its less expensive with a major leak like this.

The next installment of the ac repair story for my 1995 911:

I got some r134a with uv dye and a uv light to check for leaks, but now the compresssor clutch is not engaging. There is no voltage on the wire to the clutch, but 12 volts to the clutch gets it to engage. Is it possible that the ambient temperature is too low? It was aorund 70 F in my garage when I did this. The dash fan and the fans on the condenser run ok.