LogFAQs > #946532714

Neglecting oil changes is the quickest route to needing major repairs, or ultimately throwing a rod through the side of the block. 3k to 5k intervals max. A lot of vehicles call for 7.5k with synthetics or synthetic blends, but any oil is going to start breaking down by that point and lose some of its lubricity. Keep in mind that engine oil also acts as a form of coolant, and when a piston is sliding up and down thousands of times per minute, oil is the only thing keeping it from literally welding itself to the cylinder.