When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I'd be worried about the physical durability. Heater cores aren't designed to be out where they can take rock strikes, etc.
How about an oil cooler out of a junk yard? Lots of japanese SUVs come with them stock...