I was wondering if the silicates in antifreeze can poison and or damage a cat converter and o2 sensor. I recently had a blown head gasket on my 1995 cavalier 2.2L and now it will not pass the emission test it showed high hc. The state standard is .80 and my car came in at .83 just barely failed . I suspect that the cat and or the o2 sensor may have been poisoned or damaged by the antifreeze in the exhaust. What do you guys think?