Rusted exhaust bolts

[mrlmd1]

Isn't this one of those things that, if it ain't broke, don't fix it? If nothing is leaking and all that's bad is you don't like how it looks, then don't look at it. You can ask the shop about it the next time you have to go in there for something else, otherwise there are probably more important things in your life to think about.

The idea of heating something up with a torch is to have one part or metal expand/contract at a different rate than the other, to break apart the rust bond, a sort of welding between the 2 objects. When the engine is run, if both of the metals are of the same composition, the bond may not break as aren't both of the metals expanding and contracting together at the same rate? This is different than trying to heat up just the bolt with a torch. Or having a stainless bolt screwed into aluminum. I would still suggest not to be concerned about a cosmetic problem and concentrate on making it look nice if it really bothers you. If you have a leak, or if the bolt head snaps off (very unlikely), then the shop can get it out.

I wasn't recommending the rust converter stuff (phosphoric acid) to try and get the bolts loose, just to coat the heads of the bolts so they wouldn't rust anymore. This is not a coating, it is a chemical reaction that changes the surface and shouldn't be affected by engine heat. Then, if you don't like the blackish apprearance of the bolts, a little bit of high temp paint could solve the problem if you liked that look better.