There is a chance that some air bubbles are trapped in the cooling block itself causing some noise but over time it will move to the radiator as it's the highest point in the system. I'm not sure of the construction with the new style Asetek pumps. I took my previous generation H115i apart a few weeks ago due to cooling issues. I don't recommend doing this by the way. I found that the pump blade/impeller simply sits on a plastic pin. If that pin breaks, the blade will still turn and move the liquid but it will be unstable and cause a knocking sound since it's hitting the side walls of the housing of the pump. A little worrying that yours has a high pitched and ticking noises. Yes please upload a sound byte but if you've just bought this then maybe return it for a replacement.