Okay about 3 weeks ago I lost heat in my car and I changed the thermostat and I got my heat back. Yesterday I lost heat again notice that my coolant level was a little low. So I added to it to the full mark and I got my heat back for about a few hours. Now this morning I have no heat in my coolant level is still at full. Could it be a coincidence that my new thermostat was just bad form the get go?