I’ve got a 2003 GT mustang 4.6l. I was driving it home and the motor started to make a squeaking noise. When I pushed the clutch in the car shut down. Pulled over and the motor wouldn’t turn over as if it was seized. Let it set for about 15 minutes and then tried again and it slowly cranked over then started but was knocking. I shut it back down and pulled it home. Hour or so later I started it back up and no more knocking??? Had a slight ticking when revving. Antifreeze is clean but oil does have some small bubbles on the dip stick as if it has antifreeze mixed in, but not a lot. What happened? First time dealing with a bad motor in a mustang would it be better to drop a new one in or rebuild? And if drop a new one would a 96-98 one fit? Thank you!