Alkaline cleaners are best suited for removing gelled silicate, while acid cleaners should be used to remove rust and scale. Both types of cleaners will remove, oil, grease and solder. Each time a chemical cleaner is used, the coolant system should be thoroughly flushed twice with clean water before new coolant is added. Test the coolant's effectiveness every service interval or whenever there is evidence of corrosion or leaking seals. Don't mix blends.
Manufacturers develop products to create an optimum balance of inhibitors.
Mixing antifreezes not only reduces that effectiveness, but can create a chemical reaction that could damage the engine. Good record keeping is critical. Maintenance records should include coolant hours, test results, coolant top-off amounts, freeze point, antifreeze concentrations and any information about the addition of SCAs.