damn downpipe bolts keep getting loose...

[Mits3gts]

why do my downpipe bolts keep coming loose? i have washers and lock washers on there,tightened when cold,let it get hot and tighten again.couple days worth of driving and what do ya know..damn downpipe is rattleing and leaking again.i read something about not having the support that goes to the block may cause this problem,yet i dont see aftermarket downpipe has this bracket.i have the 2.5" rnr turboback,if that makes a difference.

 

[Anubis_4_99]

i had the same problem with my turbo 510, some datsun guy's suggested aircraft wire thru the head of the bolt and wrapped off somewhere to keep it in place, i never actuly got around to doing it so i cant vouch for how well it works, but they swore by it.. i'll look for the link they gave me and give it to you