Failing to replace your car's oil is one of the most detrimental actions you can take for your engine. Motor oil serves as the vital fluid for your car, removing debris and particles as it flows through the engine's channels and narrow spaces. Therefore, maintaining clean oil is crucial. Traveling tens of thousands of miles without an oil change can lead to severe consequences. Here's the evidence. The I Do Cars YouTube channel had the chance to dismantle a 2.3-liter EcoBoost inline-four engine from a Ford Ranger with 104,000 miles, documenting the entire process in a detailed video. Signs of neglect are evident early. The timing chain cover is coated in varnish, a clear indicator of aged, overused oil. Opening the valve cover exposes a thick layer of sludge and debris, a result of infrequent oil changes. As host Eric delves deeper, the situation worsens. A substantial layer of sludge is found at the bottom of the oil pan, along with varnish on the block, oil pump, camshafts, and crankshaft. Eric believes that the previous mechanic attempted to clean the engine by adding an oil-flush additive, which backfired by loosening the sludge and blocking several small oil passages. This, according to Eric, eventually led to the engine's oil starvation and the failure of a rod bearing. The damage was extensive, with one bearing fusing to the crankshaft and partially breaking apart. After disassembling the engine, Eric checked the Ranger's CarFax, which showed no record of oil changes in the last 50,000 miles. This suggests that the truck may have operated on the same oil throughout its latter half. Learn from this. Please ensure to change your oil regularly.