It happens . easy google and you'll find issues . Specially when People top up Coolent with TAP WATER instead of deionised water, Distilled is technically the best and most CLC should use it . Creep/microorganisms can be god aweful - specially on oil Platforms
The FIRST thing to go in Water Pump !!!!!! Had Renault Twingo Sports with Aluminum Alloy Engine Block and Aluminum Radiator . Quick google on Galvanic corrosion and you'll see Aluminum alloy is the WORST with any Metal . Engine Head and Inlet Manifold was Aluminum .
Cast Iron and Aluminum are closer together then Aluminum and Copper , so less reaction etc etc
CLC and AIO are different in terminology - ask any vendor rep that makers water kit. AIO were defined as being able to be cool CPU along with GPU in a Prebuilt kit or added . CLC is closed loop and takes modding . Custom loop is 100% up to the user . Alphacool and ekwb do not advertise their kits as CLC but AIO, asetek advertise as CLC . takes a few tech sites to use AIO on a product and has stuck since . Custom Hardline is CLC as once its done its closed loop- but we still define it as Custom loop.