A well known to me tractor is up for sale . Guy got newer tractor about 8 years ago and 1486 has gotten about 20 hours since . He decided it’s time to let it go . The blow by smells like antifreeze and you can hear bubbling in radiator after you shut it off . A JD mechanic told him head gasket but I’m not convinced. I’m going back when it hasn’t been running and check oil plug. What’s chances it’s head gasket. Also couldn’t see any water on oil or oil in water and I think he changed oil cooler a few years back .