You don't have to dismantle anything. Essentially all you have to do is drain the loop some how, refill your loop. You can refill, run a few cycles through the pump, re-drain, and refill if you want to be thorough. If your loop was built pretty clean, eg rinsing out all your parts thoroughly with either distilled water or the coolant, you shouldn't have any bits inside to worry about and can just drain and refill as I will be doing in the next few months. Having an easy way to drain and refill will make your life a lot easier; I use the extra port on the res to drain and a y-splitter on top behind everything to help fill. No need to ever disconnect any tubing or fiddle with a funnel inside my rig with a squeeze bottle.