1186 Radiator Stop Leak, Silver, Bottle, 7.0 to 9.0 pH, Flash Point (F) No Flash below 75 Degrees / TaG Closed Cup/aSTM D-56, 1.01 Specific Gravity, For Use With Automotive, Use - 1/2 Bottle in a Small Cooling System, Such As 4 Cylinders with No A/c. Use 1 Bottle for Regular Size Systems, Most 4, 6, 8 And 10 Cylinder Engines. For Larger Systems, Use 1 Bottle for Every 4 Gallons Of Cooling System Capacity.