I will be installing my heater box soon and was wondering if I can test my heater core for leaks. It's brand new , but I would hate to install it and have it leak.
I had the radiator shop tested my heater core and AC evaporator. I think he said they put 45 psi to it and watch for bubbles
Easy enough to cap off the outlet, rig a hose with fitting and connect to air compressor with 20-25Lb of pressure...
Years ago I just used a very skinny bicycle inner tube and a couple hose clamps. The rubber is soft enough to conform to the size of the inlet/outlet even if it gets wrinkled or folded over to adapt to the outlet sizes. 20-30 psi or so, dunk it in a pail of water. Worked easily enough...