In the Jan Feb Mar issue of N News, there is an article titled Keeping it Cool. It states that Prestone Antifreeze should not be use as it is an Organic Acid Technology (OAT) product and only Inorganic Additive Technology (IAT) should be used in my NAA. I have had the tractor for 2 years and have used Prestone twice. So Far, I haven't noticed any leaks, but would like to know what others use in their tractors and if I should flush and fill with another brand ASAP. Thanks.