coldfoot wrote:IME mice and rodents, where abundant, will sometimes chew up ordinary rubber wires and hoses. I don't think soy-based is required.
True, but how do you know what is "ordinary"? Wires with soy-based insulation showed up in the 90s, and they look and feel much like any other wires.
Soy-based urethane is still urethane; it just differs in a tiny residuum that affects palatability. Soy-based plasticizers are now used to harden the PVC used in wire insulation, instead of phthalate plasticizers; but the PVC insulation still looks and feels and bends like old-fashioned PVC:http://www.plastemart.com/Plastic-Techn ... -jacketing
All wiring is going this way.
I still haven't seen any proof that the soy residue is the "cause;" most evidence is anecdotal, with some older cars not suffering problems. Rodents tend to chew stuff just to wear down their teeth (which are always growing), and radiator hoses carry Et Glycol (which to their undoing) is tasty to many animals.