i don't know if i'm doing a pressure test right or im retarded
i was trying to check my coolant system for leaks. i saw a drip on my 2005 pontiac gp from the radiator on the driver's side. i connected the pressure tester stuff on the radiator gasket and couldn't get pressure to build up. i had to really lock down tight on the line to the reservoir to build pressure, and i didn't see any visible leaks, but it was losing pressure.

shouldn't i have been able to do the pressure test without blocking the line to the reservoir? i'd think that with the pressure test or the gasket or something it'd prevent any air blowback, but i don't know. this is my first time trying this