American or Chinese aluminum still follow the properties of science. Aluminum submerged in a pH above 9.0 begins corroding. Sodium molybdate will slow it down, tolytriazole will tie up the copper that will plate to it and bore holes through it. That's all you can do with it. Heater cores and radiators are cheaper than cylinder sleeves, that's why coolant is made to protect the cylinder sleeves first. Heads and aluminum blocks are extremely thick, so it takes a long time but the thin cores on radiators and heater cores will always go first. Egr coolers especially as there is a massive heat load there.