Heater core leaking... again

95 XJ, 4.0

I'm on my third heater core.. The last time it leaked, I pulled it and resoldered the leaking joint, and it lasted about a year, until I blew it out with compressed air when flushed the system.

What is the best built brand of heater core out there?

dealership replacement should last as well as the original did..... much longer (I'll assume) than a year.

Remember that your cooling system was designed for about 16-20 pounds of pressure. The solder used on the heater core wasn't intended to hold up to air compressor pressures. If you're gonna use forced air to clear something, you've gotta dial the regulator WAY down.

Yeah,
That wasn't a smart move.

I'm thinking I may have had an electrolysis issue that caused all three to leak, due to old coolant and maybe poor grounds, which I'm addressing now.
After this time,I hope to never have to change it out again. It's a real pita..