Contains Lucas heavy duty oil stabilizer. Allow 250-300 miles to stop most engine oil leaks. This product can not repair torn seals or mechanical problems. It is designed to fix minor annoying oil leaks. This product does not replace Lucas oil stabilizer. If your engine is leaking oil and you are using stabilizer, use half stabilizer and half stop leak until the leak disappears. The percentage of the stabilizer/stop-leak mixture should be the same as the percentage of your oil/stabilizer mixture, with stabilizer only.