Sounds like a clogged radiator, if the lower hose is cooler and the water pump is working.
Disconnect the upper and lower hose and let some tap water flow through the radiator from the top - it should flow out the bottom really fast.
Most original used rads that never or rarely got (reverse) flushed are more clogged than not.
Minerals in tap water create build up over time, despite anti-corrosion and anti-freeze.
Regular flushing helps, but radiators need to be recored every once in a while.
