R12 dye injection?

[ps2cho]

Is there a way to charge my R12 system with some dye when there is still some refridgerant in it?

I would like to put dye in, then top up with one can and drive it to find the leak.

Its either front of compressor or the hoses....both of which are expensive. I would like to figure it out first.

Any ideas or is it gonna require complete evac?