There are a host of different adapters made for pressure testing cooling systems. So what do you do when you need to pressure test a cooling system, and you don't have the correct radiator adapter?
I accidentally stumbled onto this tip when my pressure tester hose went bad. The end that attached to the radiator adapter blew off and I was left only with a pressure tester and a hose. Rather than repair the hose, I decided to attach the hose to the overflow nipple on the radiator. I found that as long as you have a good cap you can pressure the cooling system through the overflow nipple.
Eventually I replaced my pressure tester hose, but kept the other hose around as an alternative. I still find the opportunity to use it from time to time.