www.fighters-garage.com Take a look at the Fighters Products.they have a pressure tester..Copy it..simple thing..I used a POOL gauge and a Tire valve on a PVC Cap(2 inch).I put it on a end piece so it would be longer and you could get a clamp on it.
Fill the system with air and watch the gauge.Look/feel for leaks.It allows you to actually walk around the engine IF the air isn't leaking out as fast as you put it in!