Ignoring the need to replace your car's oil can be detrimental to your engine's health. Motor oil acts as the vital fluid for your vehicle, removing debris and particles as it flows through the engine's channels and narrow spaces. Therefore, maintaining fresh oil is crucial. Extending the oil change interval by tens of thousands of miles can lead to severe consequences. The evidence is clear from the I Do Cars YouTube channel, which documented the disassembly of a 2.3-liter EcoBoost inline-four engine from a Ford Ranger with 104,000 miles. Early signs of neglect were evident, such as the timing chain cover being coated in varnish, indicating old, overused oil. The valve cover removal exposed a thick layer of sludge and debris, a direct result of infrequent oil changes. As host Eric delved deeper, he found more sludge at the oil pan's bottom and additional varnish on the block, oil pump, camshafts, and crankshaft. Eric speculated that someone had possibly added an oil-flush additive to clean the sludge, which instead loosened it and clogged several small oil passages. This, Eric believes, led to the engine's oil starvation and the subsequent failure of a rod bearing, which fused to the crankshaft and partially disintegrated. Post-disassembly, Eric checked the Ranger's CarFax, which showed no record of oil changes in the last 50,000 miles, suggesting the truck might have been operating on the same oil throughout its latter half of life. This serves as a stark reminder: please ensure to change your oil regularly.