Hello, I have a 2005 Equinox that is overheating...

Last week I had a bad intake valve and gasket replaced. The gasket was blown and the valve was rusty..

So now the car is overheating...
First a few things:
I don't get any hot air coming in to the car when the heater is on..
I could tell the coolant was coming out of the overflow hose not anywhere else when I noticed it overheating..
I went ahead and replaced the thermostat, though when I had it out the car stayed cool.
But now the new thermostat is in and when idling, it gets hot, then cools, then gets hot then gets cool..

Any ideas on why it might be doing this?

Thanks!
Scott

 

There should be a bleed valve in the thermostat housing. Did you get all the air out of the system? You also want to have the heater on high while filling the system to make sure there is no air trapped in the heater core.