First.. here's the moral of this true story: The OP's tractor might not be seized up.
My personal true story:
It was 1970 something... I was 16 y/o and my Kubota B7100 flat out quit running in the middle of a field. Acted like it seized. Just like a bomb went off... Full Stop. No residual sputtering. I turned the key... click... nothing. No turning over at all. It was an oh $#!+ moment. I checked the oil, as I did every long workday. And it was fine.
Drove my pickup to a pay phone and called my dad. After an ear'full of him telling me where the cow ate all the engine maintenance cabbages, he continued.. And how I most likely seized the engine. He finally settled down. If I remember correctly, I shed a tear or two because I LOVED that Kubota. And if the engine was ruined because I didn't take the best care of it, then I'd let myself and my dad down. You get the idea. I was deeply crushed in my spirit. After he settled down, dad told me, in a nutshell: "Go fix it, it's your tractor now. Go check the oil, coolant, etc etc. Report back"!
I drove back to the field... I heard the radiator making grumbling sounds. Over heated! After closer inspection I found that the radiator fins were packed full of seedlings and grass clippings and dust and whatnot. I was rototilling a dry field. It was my 2nd day in that field on that job. Lots of dust and stuff in the air. I never checked the radiator fins.
I let it cool for an hour, then cleaned out the radiator fins, and let it sit a couple more hours. Check the coolant level, said a prayer, and turned the key... She fired right up.. I finished that job and reported the good news to my dad. I got a pass, and lived to tell this tale.
Tractor ran for two decades without issue.
I suppose my being so harsh regarding engine maintenance runs in my family. My dad has been dead for a while now, but his blood still flows in my veins.
Appologies to all.