i wanna know how to change my thermostat ..i see it on the top of my engine in the area near master cylinder and firewall..thermostat looks good but i could be wrong ,the thing its connected to and sitting on looks totally rusted all over ..i assume its the (thermostat housing)(looks like a small metal block) do u think i should change that and how much is that... cause im getting warm air ..i checked the coolant its good n full thanx for any help

 

I would change the thermostat and clean around that area.
It's not verry expensive.