This my first experience with your service and I sure didn't mean to start all this confusion! I was NOT talking about the plastic overflow resorvor... My son, in a different city, reports a pressure leak of coolant spraying from the side of the radiator onto the battery. It is not coming from a hose, port, or core area; but from a tank area on the side that he reports "looks like plastic instead of brass."
Instead of me driving 3 hours both ways and installing a new one myself (in his small college town), I have decided it would be prudent to have a reputable garage do it for him. Thank you!