Is there a threadlocker compound that immobilizes the bolt while cool and requires high heat to release, that can withstand very high heat and thousands of heat-cool cycles without needing to be reapplied and without deteriorating? The application is automotive-exhaust-related.
P.S. This is important factoid that I left out (since I'm getting advice on doing it a different way): this is a "non-tamper" security application. The thief would have to heat the bolts to loosen them.