I have a problem (ok. Not if it's a problem. Because the panel say optimum temperature). the upper radiator hose is heated to bubble. but the thermostat does not open. and the lower hose is cold. I have no hot air in the heating. and change the thermostat and antifreeze. can you help me please?

 

Since you did not state what year/sub-model/engine/region your car is, I'm going to guess you have some version of Accord with the F series 4cylinder engine.

When you drained/refilled your coolant, did you bleed/purge the cooling system of air using the bleeder screw on the thermostat housing?

If not then the car will never properly warm up and the thermostat will never open. But your temp gauge may peg and you may blow your head gasket if you are not careful.

 

open the bleeder bolt for a few seconds