"Loose" bolts on sheet metal parts are actually caused by cheap gaskets compressing a little. If you lock the bolts in place, you'll end up with leaks due to the inability to do a final tightening after the gaskets settle into their final shape. I like to start out with a completely straight piece of sheet metal, use a brush-on sealer like Permatex Super 300 that stays pliable for years, and tighten the bolts right the first time. Run the bolt in until all the slack is taken up, then tighten it approximately 1/4 turn further to get a little compression on the gasket. After a few days of running and a few heat/cool cycles, recheck the bolts and snug any of them that appear to be loose. Don't overdo it!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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