thermostat question

[ytr1903]

Hi,

I have a question which has probably been answered previously, but with the search down, I am desperate. I just got done replacing the water pump, radiator hoses, belts and thermostat on my 82 300D. The last thing I did was put the new thermostat in and figured that it was a no brainer. I started the car and let it idle and the car promptly overheated to 100 degrees C. I pulled the top radiator hose off and poured antifreeze down the hose (supposedly to get rid of an air lock that was in there), and ran the heater full blast, started it up and again it went to 100 degrees before I shut it down. The thermostat is an 80 degree model by the way. I know the thermostat is facing in the correct direction, or at least the same direction as the old one. Before I make a mess and pull out the thermostat, I was wondering if I am missing something or is there a bad thermostat in my car? Has anyone here gotten any bad thermostats in the past? I am ready to put the old one back in, it was working just fine.

Thanks,
Tom