Stihl MS 391 muffler bolt question

[Fishnuts2]

Looking for advice on keeping the muffler on my ms391. Pretty sure I was the first to remove the muffler and the bolts were very tight. I reinstalled the muffler bolts as tight as I dared and rechecked them hot. Muffler came loose after a few minutes so I bought new bolts with thread lock on them. Yesterday I ran maybe a half tank through it and the muffler is loose again. Is this an issue for you guys too and how do you fix it?
TIA

 

[066 redeye]

Was it blue locker on them?

 

[singinwoodwackr]

Looking for advice on keeping the muffler on my ms391. Pretty sure I was the first to remove the muffler and the bolts were very tight. I reinstalled the muffler bolts as tight as I dared and rechecked them hot. Muffler came loose after a few minutes so I bought new bolts with thread lock on them. Yesterday I ran maybe a half tank through it and the muffler is loose again. Is this an issue for you guys too and how do you fix it?
TIA

Which Loctite?

 

[Fishnuts2]

Was it blue locker on them?

It was more like a grayish paste.

 

[1Snowcat]

Blue or Red is more better!

 

[mbret2004]

Try the blue first, if you use red get the saw good and hot before trying to loosen the bolts. You might need a tad bit more heat if they won't loosen. Don't force them out!

 

[Stump Shot]

The reason it gets loose is when the muffler gets hot and expands, it squishes the gasket, when it cools and contracts leaving it loose. Usually, a re-tighten after it's been run and allowed to cool down will take care of it, Note that the big thick AM gaskets can be more problematic.
As far as Loctite products go, high heat red will do the trick on a muffler bolt that likes to loosen. Just a small dab will do. Otherwise, you may need to heat it up with a propane torch to loosen for servicing.