The advantage of an engine flush is that it can clean out the sludge that can prevents the free flow of oil through the engine, prolonging the engine's life. However, many believe engine flushes are unnecessary and can even harm the engine.
Engine flushes are designed to clear vehicles' engines of sludge, reducing the wear on the engine and ensuring they are operating at an optimal level. These flushes are particularly beneficial for older vehicles that have not had an oil change in an extended period and vehicles that have had extensive engine work. They also may be recommended after the purchase of used vehicles with unknown maintenance histories. For these vehicles, an engine flush is an easy and inexpensive means of obtaining a fresh start for their engines, prolonging their lives.
However, engine flushes are not necessary for vehicles that have been properly maintained and have had regular oil changes. Automobile manufacturers develop special maintenance schedules for their vehicles that are designed to optimize their performance. Many automobile manufacturers stress that engine flushes can harm engines, damaging their seals and bearings. In newer vehicles, damage to these parts may lead to oil leaks. In older vehicles, vehicle flushes remove sludge that may be plugging up an existing leak.