power steering cooler

Those coolers don't generally fail, usually it's a small crack or pinhole from some road debris.

Find a good high-end welding shop or hydraulics shop. Either one can fin and TIG weld the hole.

I'd start with a hydraulics shop in case it's just a failed O-ring or fitting / hose union.

Depending on the fittings I would replace with something like this or this if it's pipe fittings.

Your out of my league on this one. But I question if you have power steering coolant. I would suspect you are leaking power steering fluid from the power steering cooler. If that's the case you might be able to use a cooler made as a transmission add-on cooler to replace the leaking unit. Just my thoughts. Good luck.