Not what I expected

I recently bought a 2014 Ford Ecosport from McCarthy Toyota Tableview. I received great service from all the parties involved in the sale, however one month after I had the vehicle, I received a phone call from the dealership (the day after my first debit order went off which feels suspicious) to inform me that the vehicle had a complete engine replacement in 2016 and that they just found this out the day before. This really disturbed me and I probably wouldn't of bought the vehicle if I knew this beforehand. I specifically bought the vehicle because it had low km's for a 2014 model, only 37 000km, but being a 2016 engine, the km's are just below average. I requested that they please find out why it was replaced - but I could not get an answer, all I know, it was replaced by the warranty on the vehicle and that it was replaced by Ford SA. I'm now reminded of this every time I get into the vehicle - I'm really disappointed. I do feel that the dealership could've offered me some sort of discount on the vehicle or something to compensate for this. I feel that I paid a lot of money for the vehicle and I'm now left with this as a daily reminder. I could easily go to the ombudsman with this situation but I'm choosing to give the dealership the opportunity to react to this matter first.