Stripped Exhaust Manifold Bolt Holes: Causes, Solutions, and Prevention

If you’ve ever tried to replace your car’s exhaust manifold, you know how frustrating it can be to deal with stripped bolt holes. When the threads in the bolt hole become worn or damaged, it can make it nearly impossible to secure the manifold in place. Fortunately, there are several solutions to this common problem. In this article, we’ll explain the causes of stripped exhaust manifold bolt holes, as well as the various solutions and prevention methods available.

Causes of Stripped Exhaust Manifold Bolt Holes

There are several reasons why an exhaust manifold bolt hole might become stripped. Here are some of the most common causes:


One of the most common causes of stripped bolt holes is over-tightening. When a bolt is tightened too much, it can put excessive pressure on the threads, causing them to become damaged or worn.

Age and Corrosion

As your car’s exhaust manifold ages, it’s natural for the metal to weaken and corrode. Over time, this can cause the threads in the bolt hole to become stripped or damaged.

Improper Installation

If your exhaust manifold was installed improperly, it can put unnecessary strain on the bolt holes, causing the threads to become stripped.

How to Fix Stripped Exhaust Manifold Bolt Holes

If you’re dealing with stripped exhaust manifold bolt holes, there are several solutions available:


One of the most popular solutions for stripped bolt holes is to install a helicoil. A helicoil is a type of insert that’s placed into the damaged thread. The helicoil creates new threads for the bolt to grip onto, essentially repairing the damaged area.


Similar to a helicoil, a time-sert is another type of insert that’s used to repair damaged threads. However, unlike a helicoil, a time-sert is a solid insert that won’t twist or move.


In some cases, welding may be an option for repairing a stripped exhaust manifold bolt hole. This method involves filling the stripped hole with weld material and then re-drilling and tapping new threads. However, welding can be a complicated and difficult process, and is not recommended for novice DIYers.

Oversized Bolt

Another solution for stripped bolt holes is to use an oversized bolt. This involves using a bolt that’s slightly larger in diameter than the original bolt. The larger size can grip onto the undamaged threads and secure the exhaust manifold in place.

Prevention Methods for Stripped Exhaust Manifold Bolt Holes

Of course, the best solution for stripped exhaust manifold bolt holes is to prevent them from happening in the first place. Here are a few prevention methods:

Use a Torque Wrench

To prevent over-tightening, it’s important to use a torque wrench when installing the exhaust manifold. A torque wrench allows you to tighten the bolt to the manufacturer’s recommended torque, which can prevent damage to the threads.

Apply Anti-Seize Compound

To prevent corrosion, you can apply anti-seize compound to the bolts before installation. This can help prevent the bolts from becoming stuck or corroded over time.

Professional Installation

Finally, one of the best prevention methods is to have your exhaust manifold installed by a professional. A professional mechanic has the experience and knowledge needed to install the manifold correctly, which can prevent damage to the bolt holes.


Dealing with stripped exhaust manifold bolt holes can be a frustrating and time-consuming process. However, with the solutions and prevention methods outlined in this article, you can repair your damaged bolt holes and prevent them from happening again in the future. Remember to use a torque wrench, apply anti-seize compound, and consider professional installation to prevent stripped bolt holes.

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