I just bought a home with a 36" Viking professional range with a griddle. The range was built around 2002. Both the griddle and oven were running about 100F too hot. I pulled the knobs off, expecting to see adjustment screws in the stems. Instead, there were beads of what seemed to be silicone caulk. I pulled that caulk out which revealed the screws I had expected to find. I adjusted the settings and all seems fine for now. So, why was there silicone in there in the first place? Should I put fresh high temperature silicone back in there? Is that how they come from the factory? Is it intended to prevent the adjustment from straying? If so, it didn't. Or, was it intended to prevent people like me from diddling with the settings?