How to test a heater core [before installing]
 

Smart!

Questionable Internet suggestion #13
 

https://ecomodder.com/forum/attachme...1&d=1595632061
"Just Gorilla-tape a garden hose to the heater core!"
I do not have any idea how to seal Gorilla tape around a hose and a smaller and oddly-shaped connection. I tried twice and failed twice, although the water leaked out of the tape, not the core.

So, I cut a piece of inner tube, which barely fit over the end of the hose. I used a hose clamp and then a zip tie, as before, over the heater core opening.

The tube burst, but the core seemed to hold. I am pretty sure that was the AutoZone one.

Don't buy a used one.

Figure that out on your own, didja?

Youe heater core threads are test/repair threads but so much more than JUST test/repair threads. ... This odyssey makes a legend, Xist: "Remember that year Xist was testing and repairing a heater core...?"

This inner tube pressure tester, with refinements, would belong in the "janky tools you made that worked" thread.