Way back when I had my dealers license I sold a clean Escort to a Type A personality guy. Two month later he said his mechanic said the engine was shot. He brought it in and there as a ticking in the motor, sounded terrible. I pulled the head and a chunk of the valve seat banged around in there and it looked terrible. I was shocked how well it was running in spite of the sound. Aside from a couple rusty gas tanks (other makes) it was the only warranty repair I ever had to do.