Is Stop Leak Bad For Your Engine? Hello family, as much as I would rather post pics of people and Cars and PETS 💓 I have to strongly advise to everyone to please Do Not Use Stop - Leak in your Vehicles. It might Stop The leak, but it will also clog other parts and components of your vehicle. Many passageways are very narrow and you will experience problems in the future! Yes yes yes I understand your immediate need to Stop The Leak and your lack of funds for a major repair, but these products will RUIN your car. Best Advice : Park it or Have Towed to Steve's Certified Auto Repair. Drive around with Antifreeze or even WATER and fill it often. Use duck tape Or Fix T he P roblem.