Is this broken stud on my engine a problem?
September 15, 2024 5:47 PM Subscribe
My wife was tightening a stud holding down the valve cover on our 2005 Camry, and it snapped off. There are seven other bolts holding it together; is this a serious problem? Is there a way to extract the stump without removing the entire valve cover? What should I expect to pay to have it removed?
Picture of the broken item (on the left, circled in red), with a corresponding undamaged item (on the right , green) is at https://imgur.com/a/HaDnis2
She is a happy YouTube mechanic, while I try to leave advanced car repair to the professionals. We change the oil on all of our cars, and recently have done the brakes (pads & rotors) on a couple of them. Her brother is our source for car fixing advice.
She is a happy YouTube mechanic, while I try to leave advanced car repair to the professionals. We change the oil on all of our cars, and recently have done the brakes (pads & rotors) on a couple of them. Her brother is our source for car fixing advice.
That thread is reasonable, IMO (I have an equally old Acura).
I have had good luck using Irwin-brand extractors, personally, but of course if you're nervous a pro should be able to take care of it reasonably quickly.
posted by aramaic at 5:57 PM on September 15 [1 favorite]
I have had good luck using Irwin-brand extractors, personally, but of course if you're nervous a pro should be able to take care of it reasonably quickly.
posted by aramaic at 5:57 PM on September 15 [1 favorite]
Best answer: It looks like if you take off the valve cover there will be the remains of the bolt sticking out. If you grab it with a vise grips it might come out easily. Try that before trying to extract it.
posted by H21 at 6:20 PM on September 15 [4 favorites]
posted by H21 at 6:20 PM on September 15 [4 favorites]
Best answer: If you want to try grabbing it, note that there are specialized pliers (one brand is "Vampliers" but they're more generally referred to as screw extraction pliers) which have sharp hardened teeth at the end, specifically intended to grab things with the narrow point of the pliers.
...they'll chew up whatever you grip them on, but that's kinda the point. I mainly use them to rip staples out of PT lumber, but I have in the past used them to grip the head of a screw and rip it out of the hole, so they should work to grab the stub and then let you methodically reverse out the bolt.
They're pretty handy to have around.
posted by aramaic at 6:39 PM on September 15 [5 favorites]
...they'll chew up whatever you grip them on, but that's kinda the point. I mainly use them to rip staples out of PT lumber, but I have in the past used them to grip the head of a screw and rip it out of the hole, so they should work to grab the stub and then let you methodically reverse out the bolt.
They're pretty handy to have around.
posted by aramaic at 6:39 PM on September 15 [5 favorites]
Best answer: +1 on H21's advice. It's probably best to take the valve cover off for access and grab onto and remove what's left of the stud, though you'll probably want to change the valve cover gasket, spark plug tube seals etc at the same time unless they're newish. If a person working on cars hasn't yet developed an intuitive sense of how much force to use when tightening fasteners , investing in a small 1/4" or 3/8" drive torque wrench could help prevent this sort of grief going forward.
posted by Larry David Syndrome at 6:53 PM on September 15 [4 favorites]
posted by Larry David Syndrome at 6:53 PM on September 15 [4 favorites]
Best answer: Pro mechanics can be skilled at this process of extracting broken studs.
If you are going to DIY, I would follow what H21 said above to remove the entire valve cover and get as much of the remaining stud exposed as possible.
Then, using pliers to grip any protruding metal is good. Depending on how much is protruding, I have used a Dremel to flatten a portion of the stud into parallel faces to give a better surface from which to turn. If you are careful, you can flatten it to fit the aperture of a small wrench or crescent wrench.
I have had success using a tiny, sharp punch near the outside circumference of a broken stud. Tapping it at right angle can apply force to begin unscrewing the stud. Don't forget to load it up with penetrating oil.
Using a left-hand flute drill bit can be a next step, but make sure you have the setup to drill precisely in the center of the broken stud and vertically in line with the stud. Sometimes just the friction of the drill itself can back the stud out.
Otherwise, a screw extractor set like Irwin or others can follow.
Beyond this, there are more invasive processes which you may wish to leave to the pros, but the stud can be completely drilled out and a helical threaded metal insert with new threads can be inserted.
posted by tronec at 7:44 PM on September 15 [3 favorites]
If you are going to DIY, I would follow what H21 said above to remove the entire valve cover and get as much of the remaining stud exposed as possible.
Then, using pliers to grip any protruding metal is good. Depending on how much is protruding, I have used a Dremel to flatten a portion of the stud into parallel faces to give a better surface from which to turn. If you are careful, you can flatten it to fit the aperture of a small wrench or crescent wrench.
I have had success using a tiny, sharp punch near the outside circumference of a broken stud. Tapping it at right angle can apply force to begin unscrewing the stud. Don't forget to load it up with penetrating oil.
Using a left-hand flute drill bit can be a next step, but make sure you have the setup to drill precisely in the center of the broken stud and vertically in line with the stud. Sometimes just the friction of the drill itself can back the stud out.
Otherwise, a screw extractor set like Irwin or others can follow.
Beyond this, there are more invasive processes which you may wish to leave to the pros, but the stud can be completely drilled out and a helical threaded metal insert with new threads can be inserted.
posted by tronec at 7:44 PM on September 15 [3 favorites]
Why was she tightening it in the first place?
Valve cover bolts have surprisingly low torque specs (well, it was a surprise to me anyway). Aside from being cognizant of that, it's an easy process to take the cover off and replace the gasket. So, if you take off the valve cover to replace this stud, maybe you should replace the gasket in case it got damaged by the overtightening. Or just keep an eye out for leaks, at least.
posted by mullacc at 10:35 PM on September 15
Valve cover bolts have surprisingly low torque specs (well, it was a surprise to me anyway). Aside from being cognizant of that, it's an easy process to take the cover off and replace the gasket. So, if you take off the valve cover to replace this stud, maybe you should replace the gasket in case it got damaged by the overtightening. Or just keep an eye out for leaks, at least.
posted by mullacc at 10:35 PM on September 15
is this a serious problem?
Not very. If you do nothing at all about it, the worst it will do is seep a bit of oil. Not fast enough to endanger your engine, just enough to smell bad and keep it annoyingly filthy.
posted by flabdablet at 2:00 AM on September 16 [1 favorite]
Not very. If you do nothing at all about it, the worst it will do is seep a bit of oil. Not fast enough to endanger your engine, just enough to smell bad and keep it annoyingly filthy.
posted by flabdablet at 2:00 AM on September 16 [1 favorite]
Best answer: Is there a way to extract the stump without removing the entire valve cover?
There are a few, but none of them are worth their added risk of damaging the valve cover when they go wrong.
Taking the valve cover off will also be an opportunity to help build that feel for how tight these things should be. Use a Sharpie to make a mark on each nut that extends onto the valve cover so you can see how they sat before you started, then loosen them, then slowly and attentively torque them down again only as much as necessary to make the marks line back up. Do that for each nut as you remove the cover and your wrist will learn what to do when you replace it, even after you've invalidated the marks by mixing up all the nuts and replacing the gasket.
posted by flabdablet at 2:23 AM on September 16 [2 favorites]
There are a few, but none of them are worth their added risk of damaging the valve cover when they go wrong.
Taking the valve cover off will also be an opportunity to help build that feel for how tight these things should be. Use a Sharpie to make a mark on each nut that extends onto the valve cover so you can see how they sat before you started, then loosen them, then slowly and attentively torque them down again only as much as necessary to make the marks line back up. Do that for each nut as you remove the cover and your wrist will learn what to do when you replace it, even after you've invalidated the marks by mixing up all the nuts and replacing the gasket.
posted by flabdablet at 2:23 AM on September 16 [2 favorites]
Best answer: If you grab it with a vise grips it might come out easily
especially if you start by soaking it with WD-40, waiting ten minutes, then giving it a gentle tappy-tap-tap on the end with a hammer as you lefty-loosey it with the vise grips. Doing the WD-40 soak before removing the valve cover will save a bit of time as well as taking advantage of the capillary reservoir that exists between the gasket and the broken-off stud.
posted by flabdablet at 4:37 AM on September 16 [1 favorite]
especially if you start by soaking it with WD-40, waiting ten minutes, then giving it a gentle tappy-tap-tap on the end with a hammer as you lefty-loosey it with the vise grips. Doing the WD-40 soak before removing the valve cover will save a bit of time as well as taking advantage of the capillary reservoir that exists between the gasket and the broken-off stud.
posted by flabdablet at 4:37 AM on September 16 [1 favorite]
Response by poster: Thanks for the suggestions, everyone!
She's picking up a replacement stud today from the dealer, and will give it a try. Fingers crossed....
posted by wenestvedt at 9:36 AM on September 17
She's picking up a replacement stud today from the dealer, and will give it a try. Fingers crossed....
posted by wenestvedt at 9:36 AM on September 17
Response by poster: Update: she soaked the stud in some penetrant overnight. Removing the valve cover let me get my smallest Knipex Cobra pliers on the lowest part of the stud (with a novelty silicone wristband for cushioning!) and carefully remove it.
A replacement silicone gasket (from FedTech?) with four dabs of Permatex Ultra Red RTV silicone (per the manual), went on, and -- with some effort to get the hoses & cables out of the way -- the valve cover went back into place.
Thanks to all for advice and guidance!
posted by wenestvedt at 6:33 AM on September 19 [2 favorites]
A replacement silicone gasket (from FedTech?) with four dabs of Permatex Ultra Red RTV silicone (per the manual), went on, and -- with some effort to get the hoses & cables out of the way -- the valve cover went back into place.
Thanks to all for advice and guidance!
posted by wenestvedt at 6:33 AM on September 19 [2 favorites]
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posted by wenestvedt at 5:48 PM on September 15