Hey guys 07 Tahoe all stock, oil leak that went unrepaired and driving down the road heard a knock as if something had broken, oil pressure /dash lights came on and it seemed to loose power. It still ran till safe stopping point but very rough. Mechanic said engine needs to be replaced but never got specific diagnosis. It does have a knock but I'm thinking it's a spun bearing maybe he didn't want to deal with. Any ideas on if it could be a spun bearing or where to start? Also I know about the proper way things should be done but if there's a will there's a way. Any help appreciated.