How To Remove A Broken Bolt From An Engine Block? (4 Steps)

It can be annoying when you accidentally break your engine bolts while working your engine blocks. However, it becomes even more frustrating if you don’t know how to remove and replace it appropriately. 

So, how to remove a broken bolt from an engine block? First, you can use a spring-loaded center punch to remove the broken bolt to drill out the bolts. 

It becomes challenging to do the removal process yourself, especially if you are not using the proper tool. Also, you might break it while it is still inside, which makes it even harder to drill. 

Broken bolts can affect the engine box seriously. For example, creating a malfunction inside makes the engine stop responding correctly.

You can tell that there are broken bolts inside the engine block if you hear an unusual noise. However, removing the broken bolts in the engine box needs lots of effort and patience.

It can be done by a professional mechanic only. They know more about how it’s easier to drill out the broken bolts because they have a complete set of tools. 

Suppose you notice a broken bolt inside your car engine box. Don’t use your car any further; you can contact a home service car mechanic or let the tow service deliver your car to the car shop. 

How To Remove A Broken Bolt From An Engine Block

How To Remove A Broken Bolt From An Engine Block?

Here is the process of removing a broken bolt from an engine block:

1. Drill The Center Of The Broken Screw Slowly Using A Hard Drill Bit

Doing the first step should be done with low precision. You don’t need to hurry in this process because you might break the screw more. 

2. Make A Slow Dig Using A Center Punch

Next, use a center punch to give you a headstart when you put a new bolt. Take time to dig the portion and drill slowly to the center because you are trying to grasp it. 

3. Set The Perfect Size Of The Drilling Bit

After you are done with step 2, you can start the step 3 process by setting up the size of the drilling bit and patiently drilling out the bolt. 

4. You Can Know to Extract The Broken Bolt By Using A Mole Grip

In the last process, after loosening up the broken bolt, you can now use the mole grip to pull it out in the engine block. 

Apart from doing these steps, there are sometimes that the extractor breaks inside the screw. Making more problems to its extractor because it is made up of a rigid material won’t come out that easy. 

Moreover, the best advice if you extract the broken bolt is not to rush. Instead, keep it slow until you can see that the bolt moves safely. 

When it’s, you see that the bolt is already loosened up, still grip it slowly using the mole grip. 


A broken bolt inside an engine block is hard to extract. Because of its heavy material, it is why it needs patience and proper precision to remove the broken bolt successfully. 

It would help if you watched out when you unscrew it; sometimes, it breaks even more, making it harder to unscrew. If that happens, use a spring-loaded center punch to unscrew it easily. 

Moreover, the engine block has a tight space; if there are broken bolts near or inside it, it takes time and effort to get it out. 

You should not do it if you do not have enough knowledge of mechanics. It might be the cause that you will pay more than the price of getting the broken bolts out on the engine block.



Image credits – Canva

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more