1.4 16v Cooling Help

Apologies for the very basic mechanical knowledge that it will likely take to solve this - I am having issued!

I have recently switched over to a topfill radiator (original mk1 style) as my header tank set up was leaking like hell and a constant problem.

It's a 1.4 16v AFH engine.

I have put new coolant in and topped up but feel like I'm missing a trick, on starting the car the top hose gets hot and the bottom stays flat cold…

Thermostat problem maybe? I didn't notice it before I switched over! I ran it until I noticed that and then shut it off as I didn't want to cause any further problems.

 

http://www.vwgolfmk2.co.uk/forum/viewtopic.php?f=37&t=14913