Yeah, I wasn't sure about the aluminum. Copper core, check. But truck rad? Do smaller rads not exist with copper tubing? I'll harass my local scrapper tomorrow.
Geo cooling?? That's certainly a step further. Intriguing concept, but vastly above me right now. When using such.. innovative methods I think I'd try something using a compressor first.. But again, out of my league, budget, available space and I don't think compressors are too silent

PS. That's certainly the endeavor from zzlee. Good god, that's a work load.