I thought I had an antifreeze smell in the car several weeks ago and tried some Bar's Leaks radiator and heater core stop leak. Seemed to stop the smell. Coolant level did not go down. Now I get a strong smell in the car. Steam seems to come out of the defroster vent and the vents when put on outside air. I assume this confirms a bad heater core, but what about the leak that burns off the cat. The intake manifold has been updated and I can't see anything leaking. Can a bad heater core do this? Should I try one more can of stop leak as it states to try a second time if needed. Can not find any reason for the leak on the cat. Any help would be great.