A few months ago we purchased a second hand Mazda 2 2006 through a mechanic, who was selling it on behalf of a friend.
Mileage was around 220,000kms and there was no visible damage or mechanical issues. The mechanic told us that he had checked the car thoroughly and didn't find any problems. He also told us to ignore the engine light and minor noises coming from the engine as it was an old car, and to come back for a check up every 2,000kms.
Since he was a mechanic who we knew previously (he wasn't our regular mechanic, although we had used him a few times) and we didn't know much about cars, we trusted his word and bought the car.
A few days ago my partner was driving the car when the engine started making funny sounds. Out of caution he drove to the mechanic, but by the time he arrived the sounds got a lot worse. The mechanic checked the car and told us the engine had overheated, and it would cost almost as much as the car to replace the engine. He said that had we had gotten the car serviced earlier, he would have spotted the problem and fixed the issue. However at the time we had only driven around 2,100kms, and had not noticed anything unusual up to that point.
In hindsight we should have done more research and due diligence before purchasing the car, and it was our fault for not doing that. However I'm wondering if the mechanic was partially responsible because he had missed something in the initial checks, and sold us a car with potential or known defects.
Just wanted insights from someone with more knowledge about cars whether the car could go from being in good condition (as per the mechanic's opinion) to needing an engine replacement in a few months without any warning signs?
Not even a good enough mechanic to wipe the engine light.