Is it okay not to remove a broken cylinder head bolt?
2 Answers
It is not okay to leave a broken cylinder head bolt unremoved, as it can cause significant and severe impacts. It may directly lead to cylinder head deformation (engine operating temperatures can exceed a thousand degrees Celsius). A deformed cylinder head loses its sealing capability, resulting in oil leaks, coolant leaks, wear, and cylinder scoring—all of which can cause direct engine damage. Below are solutions for a broken cylinder head bolt: 1. If the broken part is exposed: First, try using pliers to see if it can be twisted out. If not, weld a nut onto it and then twist it out. 3. If the broken part is not exposed: If there is no exposed part, you can attempt to chip it out using small flat tools and a hammer, or drill into the bolt for extraction. It is best to have this done by a professional mechanic.
If a broken screw is left inside the cylinder head without removal, I think the risk is quite significant. That screw serves to secure the cylinder head, and if one is broken and left untouched, the pressure distribution will become unbalanced. This can easily cause the cylinder head to loosen, leading to poor sealing, and potentially resulting in leaks of engine coolant or oil. Over time, fragments might even fall into the engine interior, scratching the cylinder walls or pistons, which would then require a major overhaul. I've personally encountered this situation several times and generally recommend addressing it promptly. Have a mechanic use specialized tools to extract the broken screw—don't wait for a minor issue to escalate into a major problem. For older vehicles, regularly checking the tightness of screws can help prevent such issues.
