Mate, when you did the relocation of hoses, what happened to all the fluid in the hoses. I read an archived thread from LS1 today and the guy said that he had to drain all the coolant out of the radiator first and then poured it all back in once the hoses were changed
Sorry mate I should have explained it better yes you will need to drain your coolant. If you look under the front bar/splitter there is a hole and the coolant drain screw.
1: jack up car (can't get under mine).
2: undo drain plug for coolant approx 8-10ltrs
3:take off bottom of hoses first and let the little bit of excess dribble out.
4: fit new hoses as per the pics I sent you .
5: fill with coolant.Start car and turn the heater on to make sure coolant has gone through heater core . Easy to tell (heater works) then turn off and check your levels again.
Took me a little over an hour to do hope this info helps