I think I may have 3 stripped bolts out of the 8 that attach the runners to the plenum.

The bolts are as follows: 1- closest to the throttle body on passenger side; 2- center bottom on passenger side; and 3- center bottom on driver side. I didn't overtighten them or anything. It seemed like they were already stripped. They just keep spinning in their holes without tightening.

The rest of the other bolts are all tight. I have applied antiseize to all of them, but I don't think that's the cause.

Anyway, even though the gasket is nice and snug, I'm worried that there may be some vacuum leaks.

SO, what can I do to prevent such a problem without replacing the plenum? Can I rap the bolts with plumbing tape and/or silcone or something? Should I use larger bolts?

Any help will be much appreciated.

 

Don't replace it, repair it:



Or instead of thread inserts, you could through-drill the lower holes, tap through, install longer cap screws, and use nuts to back them up. That won't work well on the upper bolts, however. Your options are replacement, remove and weld/drill/tap, or remove and tap for thread inserts. In any event, you'll be removing it.

And of course by now you've probably discovered why the bolts should be torqued to 18 ft/lb only.

 

On one of mine it showed signs of getting weak. I bought a bottoming tap and tapped the hole in as far as I could. Bought the next longer size Torx bolt and all is well again. Don't know if that will work in your situation.