Although some leak-stop products work for transmissions and power steering, oil seals are more critical to an engine's performance and may in fact be dissolved by the additive. If the leak is small, drivers should check the oil level regularly and add oil as needed.
If the oil leak is accompanied by white exhaust smoke, that indicates a more serious problem, such as a bad oil seal. Larger leaks that are no accompanied by white exhaust smoke may be due to a rear engine seal leak, which, although a costly repair, needs to be done as soon as possible to prevent permanent damage to the engine. Running an engine completely out of oil requires a complete engine rebuild or replacement.