When parked have awesome amount of heat but going down road have cold air

What is your question?

car is parked and running it has heat awesome but going down road heat disappears what could cause it it's full on fluid but no heat until you stopped this is on a 2013 Fiat 500

What makes this problem better or worse?

Car running has great heat unto you go down road

How long has your 2013 Fiat 500 had this problem?

Bought car used