No heat

You say new thermastat. Where was the new t-stat made? If it was mexico then it could be the new t-stat.I ran into this when I put intake/head gaskets in mine in '05. I put a new t-stat in cranked it up checking for leaks and noleaks but the temp hand went up 3/4 way and stayed there no heat. Rechecked everything after it cooled off radiator full then pulled the t-stat out went and got another one. Put it in same thing. Did this 5 times each time same thing it would warm up then when the t-stat was supposed to open never did temp kept going up. Just for the hell of it we boiled some water ste it off burner dropped the new t-stat in it never opened. Got to looking at it made in mexico, as were the other 4.I had to go to 8 parts stores to get one made in usa put it in temp gauge went half way t-stat opened run like a new one. Lesson learned t-stats made in mexico ain't worth the box they come in.

My van does not have heat at all just blows cold air and it also over heats. We have changed the water pump and thermostat I'm at a lose and heard its probably needs a new heater core and a flush. Please help I'm cold and so are my three kids. Its my only means of transportation