Q: broken exhaust manifold bolt.

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How difficult is it to remove a broken exhaust manifold bolt? is this best left to the dealer or professional?

My car has 124000 miles.
My car has an automatic transmission.

If you haven’t done this before, I highly recommend taking it to someone who has experience with broken bolt removal. This is a process that requires experience or the results can be very bad. When a newer technician is taught to do this, he or she is closely guided by a more experienced person. I could explain the process, but the reality is there will be decisions that will need to be made as the process moves forward.

The first lesson with bolt removal is never be in a rush. It isn’t something you can place a flat rate time on. Each removal is a unique process in itself and it will take as long as it takes. Rushing will only lead to a much bigger problem.

Here is a general guide for you to decide if you want to take this on.

First, is it broken flush into the block? If it is, this has become much more difficult already. This requires drilling and removing with what is known as an easy out. For sure, if you haven’t done something like this before, take this to someone who has.

Second, if the bolt is sticking out and you can grab it with vice grips or pliers, give it a turn. A stud remover is a very nice tool for this situation. Keep in mind, some of these tools are made much better than others. A cheap set is not recommended. This set is simply the first one I could find on the internet. Quality pays dividends in this case. This tool is designed to remove studs, but a broken bolt is a stud at this point. I personally have a Snap-On set that I covet.

Briefly I will explain removal when you have to drill. You have to drill as closely to the center of the bolt as possible. If you don’t and you have to drill it out as opposed to using and easy out, you will end up damaging the threads of the head. You don’t want to go there. So centering is paramount to a successful flush broken bolt removal. Ideally you should buy an easy out kit which comes with left handed drill bits and some easy outs. Don’t let the name confuse you. This process can be quite easy, if you’re lucky. It can also go terribly wrong. Usually it is something in-between for those of us with experience. Cheaper easy out kits are a waste of time, so if you don’t want to spend to much money, just take it to someone else.

You will begin with a small drill bit as a center hole and progressively use a larger bit. You want to leave enough of the bolt on the circumference for the easy out to fit into and get a good bite. If the outside wall is to thin, you will just force the outside of the broken bolt against the walls of the cylinder head and will not be able to turn the bolt out.

If you made it this far, the journey is not yet over. If you were very lucky, the bolt would have come out while drilling with the left handed drill bit. If not, install the easy out gently with a small hammer and begin to turn it. There are tools for turning the easy outs but a wrench or pliers will typically work. Warning This next point is critical. Do not break the easy out inside of the broken bolt. This is the worst case scenario. An easy out is high carbon steel that is harder than any drill bit, unless it is diamond. If it breaks in there, good luck to you! These bits have higher breaking points, but they do not bend or flex before they break. They are brittle and when they break, they break suddenly. So make sure you don’t see any twisting when turning the easy out. I know the feel of a easy out getting ready to break. I only know because I have been there.

If you would like to have this repair taken care of, a certified technician from YourMechanic can come to your car’s location to repair the bolt for you or can replace the exhaust manifold if needed.

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