Majour flow issues... help urgently needed

[Fluxcore]

Looks to me like your Rad is airLocked
B.T.W I have fixed these Lo-pressure Rads with 2 part epox . Just make sure it is drained and dry .Scrape/sand the punture
The apply the epox. works good . or if you have access to it use gastank repair epox.
If you want to see if it is Airlocked just turn your Rad/computer on its side.Out let side up and turn on the pump.that will force the air out of your rad.Or just take out your rad and turn it so the inlet/outlet are on top.