Its not a problem at all. Hot water goes out the top hose to the top of the radiator and flows down. At this time of year the bottom of the radiator and bottom hose should be cold. In winter, when youre using the heater, diesel engines struggle even to warm the the top hose up unless you're bombing down the motorway and have done at least 5 or 6 miles.
The only thing to watch is the temperature gauge - if its showing normal, everything is AOK!