Will be! This is not a general problem. I wouldn't say it's corrosion either. The coolant contains the appropriate additives so that nothing can actually corrode. I'd say it's more likely residue in the radiator. If you buy a separate new radiator, you have to rinse it before installation to remove the last production residues. This probably did not happen or happened insufficiently with the AIO. I assume that the replacement AIO is OK.And the corrosion . Change a new one and is it good?