BigJim If what you say is true, why don't the Antifreeze makers recommend using more? Not using a 50/50 mix would result in double the sales. It's not ethylene glycol that inhibits corrosion, it's other additives, some of which are abrasive and can reduce the life of seals. Using more antifreeze can reduce water pump life and radiator efficiency. In the south you might not need to be concerned about the temp dropping below 0 but a lot of vehicles are running around with borderline systems that need all the help they can get to avoid overheating. The slight reduction in efficiency caused by using straight AF could be the straw that breaks the camels back. If a proper mix is maintained and the coolant is changed when it should be, corrosion will be nil with a 50/50 mix.