Posted on 10/31/2025
Fresh oil does a lot of heavy lifting inside your engine. It reduces friction, carries away heat, suspends contaminants, and seals tiny clearances so parts move smoothly. As miles and months pass, that same oil slowly loses the qualities that make it protective. If it stays in service too long, wear starts to climb and small problems begin to stack up. Here is what really happens when oil ages past its useful life and how to keep your engine safe. Why Oil Breaks Down Over Time Every heat cycle changes oil at a molecular level. High temperatures thin it out, then cool downs thicken it again. Oxygen reacts with the base oil and starts oxidation. Fuel and moisture mix in during short trips. Detergents and dispersants get used up holding grit and soot. Eventually the oil cannot do its job as well as it did on day one. It still looks like oil, but its protective film is weaker and less stable under load. Viscosity Drift and Cold Start Wear Engines need ... read more