I've been using Dex-cool for about 15 years and 60,000 miles without any issues at all, just wondering if others are also using it and had problems. The reason I switched at around 23,000 miles was, when changing the antifreeze (green type), I noticed a lot of hard crud and pitting around the thermostat, the hose connections and the radiator cap. Since using Dex-cool I have had the radiator out for various reasons, more recently to change a stuck thermostat and most recently to install a poor boy-style alternator conversion. The Dex cool always looks like new, no pitting, no crud and the radiator and water pump looks squeaky clean. Any thoughts on this?