Assuming the radiator pressure tester is good, how should I test the new radiator?
1. fill with coolant then pressurize?

2. pressurize and wait to see if gauge drops?

Is air-only test fair when testing for liquid, or is it about the same?

Thank you in advance.

 

Fill the system pressurize it to 13-16 psi and watch for pressure drop or check for leaks.
But why do you want to test a new radiator?

 

Best to test It with coolant in it, If you just test it with air its going to push air pockets around and give you false readings. It also helps to find other leaks if the rad wasn't your only problem.

 

Thank you for the replies. I don't want to do this again, having been through multiple changes for other things. Also saw a few stories of leaking new radiator, after the install.