There are many instances where someone has neglected oil change intervals and have not had an issue. Oil overheats and turn to fudge like varnish and sticks to the parts inside. Problems arise after someone starts oil changes and the new oil additives start to clean and break away the sludge which clogs the passages and causes a death due to oil starvation. Seen this many times after someone gets their new used vehicle and starts maintenance. Key is to keep it clean from the start to avoid problems.