Review on Dorman 902 109 Thermostat Housing by Jennings Ford

I spent 3 hours getting this thermostat housing for my 2001 Daewoo Lanos to work but couldn't stop it from leaking even when the car wasn't running . I've removed the case and tried reinstalling it many times, changing the hoses and tightening/loosening the bolts, but nothing worked. There seemed to be a leak between two pieces of metal that were meant to be sealed with a piece of rubber wrapped around the actual thermostat. I finally gave in and bought a (solid) plastic thermostat housing and it worked on the first try. Maybe my product was defective.?