Is cleaning inside of car engine necessary? Internal engine cleaning requires specific methods, such as engine flush products or decarbonisation techniques. These processes aid in the dissolution of pollutants and sludge within the engine, which are then flushed out with old oil during oil changes. Modern engines with tight tolerances benefit especially from such cleaning techniques, which improve efficiency and lifetime. Internal engine cleaning is beneficial, but it should be done carefully. Over-cleaning can occasionally destroy necessary protective layers or cause oil leaks in older engines. Most manufacturers advocate cleaning only when absolutely essential, usually when symptoms such as poor performance or excessive oil use arise. Following your vehicle's maintenance plan is critical for determining when cleaning is necessary.