Kawasaki mule with rust in the oil pan?

[Michael]

I have a kawasaki mule 3010 gas. it's been running really sluggish and the oil temp light came on yesterday while driving. I checked the oil and as soon as I pulled the dipstick i could smell burning. I just changed the oil two months ago and didn't notice anything wrong. but yesterday the oil was full of rust. Since the engine is sealed i couldn't figure out how water could have gotten in to rust it. It's run every day so it's not like it just sits and water seeped in. Possibly blown head gasket? maybe coolant leaking from somewhere? please help