1995 Quad 4 Grand am overheating help

I have a 1995 Grand am quad 4, when I crank it , It will set there and run cool at idle for about 20 minutes but when I go down the road and go about 6 miles it will go to 280 degrees and this just started after putting a new thermostat housing on it, and I have since changed the thermostat and it still overheats like it has an air pocket. Thought maybe it may be a head gasket, but does not show signs of it. No smell, no steam out exhaust, So does anybody have a suggestion?

Welcome to AF.

Did it do the same thing, overheat, before you replaced the thermostat ?

Was the thermostat installed the right way ?
Spring goes inside hte motor....

I would try purging any air from the system.
Let it idle with the radiator/resivoir cap off and see if the coolant level drops.

You could have a blown head gasket and have no signs externaly at first. Over time is what causes it to blow oil or coolant, either into the oil or exhaust.

Also is the cooling fan kicking on when it gets realy hot ?