You’re about to finish a valve cover gasket repair. Everything is running smoothly, and you’re looking forward to having the job finished.
That last bolt is about to slip into place. As you get closer to the final turn, it feels like the hardware gets stuck. You try to twist it one more time, and then the unthinkable happens.
The bolt breaks while it’s getting tightened in the engine block.
What happens next depends on the circumstances you face. This guide goes over your options to repair this situation if it happens.
Broke a Bolt While Doing My Valve Cover Gasket
One broken or missing bolt can cause significant damage to a vehicle. The problems it causes are part of the reason why this issue is often referred to as a “mechanic’s worst nightmare.” The easiest way to remove the bolt is to grab a nub and twist it out manually with a Vice-like tool.
Several methods are worth considering when you have a bolt break while working on your valve cover gasket. Each one is based on the circumstances you face when the component exposes its fault.
None of the potential fixes for a broken bolt are easy to complete. You might find that one method needs to be abandoned because it isn’t working out as expected.
The best scenario in this circumstance is to have access to an extended nub for the broken bolt. You can grab or clamp it with some Vice Grips, but that depends on how much is available to access.
It might help to add some lubrication to the components to facilitate their ability to start turning.
Most mechanics need to drill down the center of the broken bolt. Once you have space to access the component, you can insert a screw extractor to remove the problem.
This work requires specialized knowledge. If you drill too far or make an error, you can severely damage the engine castings.
It’s highly recommended that if you cannot extract the bolt with your tools, speak with a trained technician to ensure the broken bolt is removed.
How to Remove a Broken Bolt from Your Engine Block
If you want to try drilling out the broken bolt, here are the steps to follow so that you can remove the component successfully.
1. Use a Center Punch
The first step is to use a center punch to create a dig in the broken bolt. Without a cavity for the bit to work, it’s more likely that it’ll wander and cause damage.
Take your time to line up the punch to the correct space. Once you’re satisfied with where it needs to be, create the dig point.
A hardened steel centering punch works the best. Use a hammer to strike it that doesn’t place an extra burden on your wrist or arm.
You want it to be as perfectly centered as possible to create the desired outcome.
2. Drill the Center of the Screw
You’ll need a hardened drill bit available that can cut through the bolt metal that got stuck in the block. It should be rated for this type of work.
The drill bit needs to be smaller than the bolt itself to have a successful experience. It should be at least 1/8-inch less than the bolt diameter, but it might help to use an even smaller tool for this step.
You must drill through the center of the screw. Take your time to avoid causing additional damage to the engine. The goal should be to drill as little as possible to create a strong latch on the broken item.
Do not move the drill bit beyond the center of the broken bolt to ensure damage doesn’t occur while working.
3. Use the Bolt Remover
You’ll need to measure the thread width and purchase the appropriate bolt remover for it if you don’t have one available.
Bolt removers are tapered screws that come threaded counterclockwise, which is the reverse direction of the bolt.
That allows it to unscrew in the opposite direction, working to free the broken bolt from the engine block.
You might get asked to enlarge the hole in the bolt in the instructions for the remover. Follow those guidelines to the letter to ensure the results meet your expectations.
Once it reaches the taper, you can unscrew the stuck bolt from the block.
4. Remove the Stuck Bolt
It can take some work to nudge the broken bolt out of the block while changing your valve cover gasket.
A high-quality wrench or socket helps to generate the leverage needed to have a successful experience.
When Should I Replace My Valve Cover Gasket?
Most automakers don’t provide maintenance requirements for valve cover gaskets. That means the only time it is necessary to replace it is if the product begins to look like it is leaking oil or causes the cover to shift.
When the valve cover gasket is old, the product is usually replaced when completing a major engine repair.
The valve cover is responsible for protecting the valve train components at the top of an engine. The gasket seals the gap between the cover and cylinder head.
As time passes and frequent high temps occur, the gasket starts shrinking or becomes brittle.
If you suspect that you have a faulty valve cover gasket, the symptoms include leaked oil on the engine, smelling burnt oil while driving, and seeing visible traces of a leak underneath the vehicle.
Since other components can generate oil leaks, you may need to observe the engine’s functioning to determine if the liquid is coming from between the cover and the cylinder head.
Some oil leaks are clearly visible, while others might be difficult to diagnose.
When it’s time to replace the gasket, most drivers can do the work themselves. A four-cylinder engine is a straightforward job.
You just need the gasket and a sealant to give yourself a strong surface on the corners and tight spots with the shape.
If you’ve finished that work and a bolt sticks or breaks, you’d need to remove it to complete the repair.
No amount of sealant will plug up that hole permanently, and you’ll be stuck with more oil leaking and a potentially fouled gasket.
What Happens If I Drive with a Leaking Valve Cover Gasket?
You might get asked to drive for a few days after a mechanic cleans up your oil leak to ensure the gasket is the problem.
Some leaks aren’t bad, and it’s now unusual for older engines to develop sweating in this area that can look like oil is leaving the system.
If your motor isn’t losing anything and you don’t see droplets form while parked, you might be able to put off the repair.
When you smell burnt oil, the gasket should be inspected to determine if it needs to be replaced. Smelling those vapors is not healthy.
It is possible for an oil leak coming from a valve cover gasket problem to damage the drive belt. Whenever you see oil that shouldn’t be present underneath the hood, it’s worth looking into the problem.
If you decide to tackle this issue yourself, here are the steps to follow.
- Inspect the valve cover bottom at the rear of the assembly. If it is shiny because oil is there, you likely need a replacement. When the bolts feel like they’re bottoming out, you can add a couple of washers to correct the problem.
- Cork gaskets are a popular choice for the rough surfaces between cast-iron joints. It compresses as time passes, requiring the bolts to be tightened more.
- Remove the cover and any gasket or sealant from each head. Avoid the drill hole to keep debris from going into the engine. Soak up extra oil the you see.
- Clean the bolt holes by turning a 3/16-inch bit by hand. This step cleans out the buildup that can prevent the bolts from tightening.
- Count the number of turns it takes to take the bolt out all the way. That’s how many times you’ll need to send it back.
- Block off the baffles while scraping the old gasket from the cover. Clean the area so that it is ready for the new product.
- Use a straightedge on the gasket surfaces to see if the cover is bent. They tend to deform around the bolt holes, so you won’t get a tight seal until it gets fixed.
- Once cleaned, place the gasket where indicated and bolt the cover back into place.
Broken bolts while replacing a valve cover gasket are a preventable headache. By cleaning the holes and ensuring the threads are properly lubricated, the hardware should move smoothly with appropriate pressure applied.
It isn’t easy to drill out a broken bolt, especially when it is in a difficult location to access. If you have any trouble trying to implement the advice offered in this guide, please contact a skilled mechanic. Never attempt to do something with this task if you haven’t done it before.
