Heater core developed a slight leak

[texfj40]

'71 FJ40 front header core. I removed the core from the heater, now how do I find the leak and/or should I attempt soldering or take it to a radiator shop?

 

[Pighead]

Finding the leak should be easy. I think I'd put it in a bucket of water and look for bubbles.
I tried soldering on a radiator once, found I had neither the tools nor the skills to do a good job. I vote you take it to a shop and get it done right. Unless you got mad skills or your heater core is really easy to remove and replace...

 

[FF LC FREAK]

Or just buy a new one from your local Schucks/O'Reilleys auto parts for $56. Link ---> While we find your parts, please enter your ZIP Code at CSK Auto