rattling noise at low RPM

me thinks before you discover answers to the numerous questions you have there is an option of applying exhaust tape from a nearby autostore between the exhaust pipe and the heatshield to kill some of that and save some $$$.

here's one example, nevermind the moto application

yes, yes, and yes. Usually repair - usually by welding or clamping

Yousuf Khan:

In some jurisdictions it is illegal to weld exhaust systems. Clamps and bolts are required, because welds are prone fail under the vibration that the exhaust system experience.

Name one. They are ALL welded from the factory. And welding the heat sheild is NOT welding the exhaust anyway.(technically).

I've had more clamps let go (on stainless steel systems) than welds over the last 15 years. The clamps rot off unless you use high quality (read expensive) stainless steel clamps.

I'm curious, do you use any loctite (blue or red) on clamp bolts or it disintegrates at the exhaust temperatures so there's no point?

They actually ended up removing the right-side heat shield! There is apparently two catalytic converters and only the right-side heat shield was loose, so they took it off. Is this okay?

Yousuf Khan

no, they should have clamped it GW

Davoud:

Yousuf Khan:

It's OK by me, but I don't know what the law says in your jurisdiction, or if there is a federal law.

It's worth remembering that the earliest catalytic converters did not have heat shields. Then there were a few cases in which people parked their cars in high, dry grass and the enormous heat set the grass afire, burning the vehicle and, in some cases, spreading to become more damaging fires. So watch where you park.

I've had a number of Subies over the years since 1989, one of them, I don't remember which one, rattled and needed the heat shield rrepaired. The dealer said they welded it. It seems to be a common occurrence and practice to weld them. They are not part of the exhaust, but part of the chassis surrounding the exhaust.

No it is not. They are there for a reason. Don't park in long dry grass or you may find out firsthand ONE of the reasons.

Definitely no federal law about welding exhaust parts if that's what you mean - and the law states no emission control device may be modified - so if it is fastened to the converter and not the floor you COULD take that to mean the heat sheild cannot be removed, if you stretch things a wee bit.

They are a SAFETY item, basically.

Loc-tite lets go at the high end of exhaut temps - I never use it on exhaust clamps - they tend to become self locking in a few weeks anyway - . Stover nuts work better than lock washers if you do need to lock the clamp. Or just hit them with the welder when you get them tight.

I have to assume no reason to lubricate the threads in this application to allow for lower wear and tear when the clamps rot and you are reusing a stover? or there is some lubricant that can withstand exhaust temps for a few years

Ok, kinda makes sense to use a new bolt with a new stover nut on a new application. esp if you have spent the money on a better ($$$) clamp in the first place

Any situations you can think of when you want to drill through and safety wire the thing together?

The stover will be unuseable by the time the clamp rots off no matter what you put on it. If you use stainless clamps it is a good idea to lubricate the threads for assembly so they don't gall and seize while you are tightening them in the first place.

Mabee on an airplane.