Lucas oil stabilizer is safe to use in all types of engines. As of 2015, Lucas produces two kinds of oil stabilizers: pure synthetic stabilizer for smaller or newer vehicles, and heavy duty stabilizer for larger, older ones.
Drivers should begin using oil stabilizer in their vehicles after the break-in period recommended by the manufacturer. The stabilizer needs to be added with every oil change, using a ratio of 20-percent stabilizer to 80-percent oil. Drivers can also use the stabilizer to improve transmission performance, using a ratio of 25-percent stabilizer to 75-percent oil in a manual transmission, and 50-percent stabilizer to 50-percent oil in a differential.