[dontlifttoshift]

To use the dye you have to charge it.

Buy a cheap set of gauges, used or hammer freight, whatever. Adapt the manifold where the yellow service hose would go to an air chuck and connect it to shop air. Now you can easily pressurize the system and spray it with soapy water and look for bubbles to find a leak. You can also just leave it pressurized to make sure it holds. I have had several cars pass a vacuum test and fail this test so now I do both on new installs.