How to remove nuts from the exhaust pipe?

Just finished helping a friend replace a tinker toy turbo on a Chevy Sonic. Four hours to install a few exhaust manifold bolts. Anything is easier to work on.

For Chrysler products, you'll get gray hair by the time you're done. Instead, the job is a lot easier if you just cut the bolt in half with an air-powered cutoff tool. The square nut you're referring to was either held on with four tiny spot welds or with a stamped steel cage to hold it from spinning on the assembly line. Those little plates were never meant to hold the nuts once they get rusty. Any replacement bolt will work. Replacement manifolds even come with a new pair of bolts and nuts. No one expects you to reuse the old bolts and nuts.

This goes back to the 1960s with this design. GM used three studs that always snapped off. What was left in the manifold went into "blind" threaded holes. The remaining parts had to be drilled out and the holes were always at wild angles. I ran into these every week when working at an exhaust shop. Very frustrating and time-consuming. Chrysler's design is a whole lot better for frazzled nerves.

Another approach, if you have one, is to cut the bolt with an acetylene torch. The holes in the manifold are usually plenty large enough in case a blob of molten metal is left on the bolt. If you still have to pound the bolt out, it's better to recut it to remove that excess metal. If you hammer the bolt out, don't get carried away. The manifold is made of cast iron, which is brittle. You'll have more frustration if the ear is cracked off.

Let me know if this works for you.

I don't like to hear that. When helping my friend in his shop, he always unbolts the exhaust manifolds from the heads and leaves them behind. Heads are heavy enough without lifting more up and out of the way than necessary. Chrysler usually uses one stud in front and one in back to hang the manifold in place, then the rest are bolts. Look into doing it that way. If the studs are too long to allow you to pull the manifold back far enough, use a pair of nuts jambed against each other, then you can turn the studs out with a wrench. They always come out pretty easily.

Are you still referring to the bolt with the spinning nut, or did you move to the studs holding the manifold to the head, and now those are also causing trouble?

Rats. I'll wait to hear how the grinder works out. I use one with a rather aggressive bit for stretching out lower strut mounting holes on GM cars to make them alignable. My only suggestion is to wear latex gloves so you won't be picking metal particles out of your hands. Safety glasses too, ... Not for your hands, ... For your eyes.

Those look like they could be correct, but you're over-thinking this. I worked at a Sears Auto Center for seven years doing a real lot of exhaust work. For the Chryslers, we just dropped down standard bolts, then put the nuts on from down below. The stamped steel cages will hold the nuts up on top if you choose to use them, but it's likely you'll have the same problem getting them off the next time. They're really meant to hold the nuts in place and from spinning on the assembly line. Same with the round steel clips on a wheel stud used to hold the brake drums on while the frame is flipped over on the assembly line. Once broken off to remove them, they get thrown away and never replaced.

A better alternative would be to weld on a metal ear or anything onto the bolt head so that bolt can't spin, and drop that down from on top. From underneath, use a little high-temperature anti-seize compound on the threads, then spin the nuts on from below.