cooling systemApril 13, 2011April 14, 2011my mechanic told me he put some material in the cooling system to mend a problem in the system what is it please? Keywords:Cooling SystemStop Leak 1 thought on “cooling system” Kristen April 14, 2011 at 9:14 am The Majic fix all for most “Small” coolant leaks is a product called “Bar’s Stop Leak”. I preffer the pellet form that comes in a bottle. Put it in the radiator (not the overflow) and run the engine for around 30 minutes or so. You can drive it if you wish. Let it cool and then check your coolant levels and you should be good to go. Comments are closed.