My downpipe is loose on my 740 turbo 1990. I took it to my mechanic and he said it needed a donut lol? I had this same problem about yr and a half ago but a muffler shop just tighten up the bolt, but now its a little worse making noises when driving. Do I need a new bolt?

 

what turbo do you have?

I would go ahead and replace the studs and nuts all together. make sure you align the downpipe...don't have to, but then i'm a stickler for that kind of thing.

I recently did this myself, good stuff...if the studs get stuck, buy a drill tap...you should be able to find it at a hardware store...for my studs, the size for the tap was 8mm X 1.25. you can either buy the tool for wrenching it in or just use a 7mm socket and wrench...good luck.

 

stock turbo maybe it needs a new flange?

 

possibly, but would you replace the flanges or replace the entire downpipe? how would you get the flange(s) off?
are the flanges super-rusted?