If it’s a 1.5 or 1.6 L ecoboost especially the 1.5, the blocks are prone to cracking which would allow coolant to enter the crankcase and lead to overheating. And you know what can happen if a serious issue like that isn’t addressed immediately. I would assume the average owner wouldn’t realize the severity of that particular problem and most likely continue driving it not knowing a ticking time bomb that lies ahead of them.