TECHNICAL DATA SHEET ENGINE OIL STOP LEAK PRODUCT # 10278, 10279 it Fy TYPICAL API Gravity D-1298 21.1 Specific Gravity @ 60°F D-1298 9273 Density @ 60°F D-1298 7.727 Viscosity @ 100°C cSt D-445 38 Flash Point, COC °F D-92 435 Color Amber Lucas Engine Oil Stop Leak is a unique formulation of Lucas additives and base stocks designed to stop leaks in engines. It is also an exceptional additive for worn and older engines, reducing engine noise and oil consumption while raising oll pressure.