The heat is probably frying the thread locking compound.
You talk about the muffler threading on to a female couupling and then mention bolts so I'm a bit confused. If you are talking about bolts the have you tried using lock washers? I'm partial to the split ring style.
If you are talking the muffler itself then I don't know of lock washers that are large enough.
If I remember correctly they use an NPT ( National Pipe Thread) setup which means there is a slight taper to the hole and the thread. If you tighten the part its supposed to jam in pretty tight due to the taper. Is there anyone out there that can confirm this? Is there such a thing as high temperature threading compound?
BTW - I'd talk to the local L&G they must know how to fix this.
This message was modified Mar 1, 2007 by nibbler