Replace Heater core

Hello there, the heater core on my Diamante went out at 45,000 miles. I am now at 111,000. I finally have the money to fix it and am wondering if it is worth it to fix or to try and sell and get something else. I have done a lot of research and this part goes out on the majority of Diamantes and do not want to buy a part I know is going to go out again. My mechanic tried to get an after market part but this came up as a dealer only part. I called up a Mitsubishi parts dealer and they said that is normal wear and tear and that they do not have any issues once they replace but he sounded like he was just full of it. Can anyone give me a better idea about my options for finding a better heater core or if it is even worth is to tackle the issue. My car runs great otherwise.

It’s almost always less expensive to fix the car you have.
If you are otherwise happy with it, keep it. This time, flush the coolant every two or three years, and the heater core should last a lot longer.
If you’re not that happy with it, sell it. It will probably be easier to sell if you fix the heater core first.

You could try to find a salvage one and have it “cooked out” by a radiator shop, but you probably wouldn’t really be gaining much.

I guess I would talk to a full fledge radiator shop first for the availability of after-market or the potential for fixing the one that is in there.

You have driven 66000 miles without a heater, what made you decide you need one now?