Finally, Si-OAT is a form of HOAT coolant that is purple — it's found in Mercedes-Benz, Audi, Volkswagen, and Porsche vehicles. The best way to be completely sure you're getting the right ...

In contrast, others need OAT (Organic Acid Technology) or HOAT (Hybrid Organic Acid Technology) that come in red, pink, purple, yellow, or other colors. Using the wrong coolant might lead to ...