Cool-Gard II is the coolant that is designed to extend the life of your engine. This remarkable coolant protects against corrosion, cavitation and deposits under the harshest conditions. And to make sure John Deere develops the best coolant to protect against these conditions, we’ve put Cool-Gard II through very aggressive high thermal load tests (*). We compared how Cool-Gard II protects common cooling system metals under these extreme conditions with how other coolants protect under the same conditions. The proven advanced oxidation stability provides long-lasting protection against heat.