I tried all the flushing products available after my 2005 Mustang started to overheat. I even tried putting on 3-4 pieces at a time. Nothing worked. Radiator, thermostat and pump replaced. Again nothing helps. Remembering I had an old rod leak in the system, I thought I should give this product one last try before pulling heads. When I turned it over, flushed it with ThoroFlush after a hard ride, it all flowed out. Even particles of trapped molding sand from the block. Saved me thousands of repairs. Thank you very much!