Stripped engine bolt threads during installation
Threads often strip or catch under minimal force during installation or removal, trapping metal shavings and preventing bolts from seating fully. This leaves hardware loose or cross-threaded, making components like headers and alternators impossible to secure properly.
What the numbers show
Counted from the threads quoted below. How we count
- Most of it landed at once — the busiest month was September 2026, with 6 people.
- This comes up 10.9× more often in r/MechanicAdvice than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Using a thread chaser with greaseDid this help you?
- 2Blowing out the hole with compressed air before installing a new boltDid this help you?
- 3Welding the broken stud (though advised against)Did this help you?
- 4Using thin copper wire as a temporary thread fillerDid this help you?
- 5Using JB WeldDid this help you?
- 6Using a longer bolt if the hole goes all the way throughDid this help you?
- 7Removing surrounding components like the ABS module to gain clearance for a right-angle drillDid this help you?
- 8Pulling a replacement bracket from a junkyardDid this help you?
- 9applying threadlocker and reinstalling without tappingDid this help you?
- 10tapping the hole to a larger sizeDid this help you?
- 11Using a hammer and sharp chisel to create an indentation and tap the bolt in a counterclockwise directionDid this help you?
- 12Cutting a notch into the bolt head with a Dremel for better leverage and using a long screwdriver and hammer to rotate itDid this help you?
- 13Taking the vehicle to a repair shopDid this help you?
- 14Cleaning up the threads in the engine head.Did this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Working on a non running N47 mini diesel and eventually got the plugs out, two of them misthread as you can see.”source ↗
“It went in normal with a 1/4 wrench not a lot of force, and when I took it out, all these metal shavings came with it.”source ↗
“I think this thing made things worse, the bolts would go in my header holes just fine, except one where it would only make it half way.”source ↗
“i stripped out a bolt hole completely like a dumbass when replacing the main passenger side hydraulic motor mount on my 08 civic. its in a really tight spot i dont think i can drill it out to put in a heli coil. what should i do??”source ↗
“Now i have some cool ARp’s and they’re giving me a hard time.”source ↗
“that spot on the 08 civic is a nightmare, had same issue with my old one.”source ↗
“I stripped out the same mount on an 02 Odyssey.”source ↗
“Tried to change serpentine belt and tensioner by myself this T50 bolt started to strip. Any advice? Do I just take it to a shop at this point lol”source ↗
“Yes originally i had that mounting bolt removed initially and then the other bolt (T50) i tried to remove but started to strip. It has to come off to get the whole part off.”source ↗
“I tightened down the top nut that attaches the harness to the alternator and ended up stripping he bolt. What do I do?”source ↗
“I removed exhaust manifold bolts on my 01 f250 7.3L, managed to get all 8 bolts out but as you can see one of the exhaust manifold bolt holes in the middle of the head is missing material on top.”source ↗
“It’s my vehicle, but wouldn’t tapping it to a larger size just result in even less threads?”source ↗
Where this came up
People with this problem also raised
- 5How to find a replacement engine bolt without measuring another one
- 17Why am I paying for broken bolts during a car repair?
- 57How to remove a stripped recessed retaining screw
- 12How to fix a stripped screw hole that won't hold
- 6How to get a blown spark plug out of engine threads
- 3Tie rod jam nut rusted solid and won't turn