Any idea what the flow rate is in your loop? I ask cause I had an issue where the radiators I had had paint overspray on the threads, I didn't pay attention to it and it bit me in the rear. Got the loop put together and everything looks great the first 24 hours, but after getting all the air out and it running for a couple of days my flow dropped like a rock, from a nice 1.5gpm to a measly .9gpm at the same pump speed. Not saying this is your issue, but if flow gets blocked enough it can create problems later, one of them being heat build up. When you take it apart to add another rad, do yourself a favor and check the CPU block for any material, its the easiest to take apart and assemble, if it's blocked there is a likely hood that your gpu is also blocked, but use your discretion taking it apart, the EK gpu blocks are a pain to put back together unless they have a formed rubber gasket.
BTW nice looking loop, I really like the hardline tubing, I so wanted to put dye in my system, but it turns out the clear tubing with water just make it look like glass rods in your system, so trick looking.
