I was wondering if I should replace the heater core before I install it in the box and into the car. They have to get weak after constant pressurization. And if I replace it has any one bought one from YO, and are they as well built as the original? Thanks

I replaced mine during my build (65 dart). Didn't want to chance it leaking on my new carpet. If I hadn't of spent it on that it would have went on something else but I've very rarely ever had one leak