The type of glycol isn't the issue, it's the corrosion inhibitors. Google inorganic acid technology vs organic acid technology, vs hybrid organic acid technology. The key is to pick one and don't contaminate it. Some types of radiators can be damaged by the IAT and HOAT coolants. The only example I know of are brazed aluminum radiators used by John Deere. Some diesels need additional cavitation protection. Fully formulated generally refers to cavitation protection. If you do go with a conventional IAT coolant they need regular supplementation (SCA).