Some online retailers that sell additives to stop leaks are Wal-Mart and Advance Auto Parts. These products are also available at retailers such as AutoZone, which offer car parts and other automobile products.
The Advance Auto Parts site features a variety of these product types from different manufacturers, including Lucas Oil Products, Bar's Leaks and CD-2 Chemicals. Most of these additives that stop oil leaks in engines are suitable for synthetic motor oil types.
The Wal-Mart website also sells different brands of these items. Customers can find these products by navigating to the "Motor Oil Transmission Fluid & Car Lubricant" section, which in found in the "Auto & Tires" subcategory of the "Auto & Home Improvement" category, as of 2015.
The AutoZone website also has different brands of additives, including STP, Bar's Leak and Lucas Oil Products. However, these products are unavailable for home shipping. Customers can get these products from a local AutoZone store.