How To Fix a Stripped Spark Plug Hole

Okay, so the threads are gone and your spark plug hole can’t hold on to the spark plug. This is a fairly common issue.

Spark plugs are supposed to be changed every 30-90 thousand miles, so they’re pretty durable. However, when they sit there for too long, it can be a nightmare to get them out, causing the threading to strip.

Don’t panic, because there’s a straightforward way to go about fixing a stripped spark plug hole. Let’s talk about it!

How to Fix a Stripped Spark Plug

For this, you’ll need to buy a thread repair kit. These are commonly found at most auto stores. Inside the kit, you’ll find wall inserts, a drill, a tap, and an installation tool, called a mandrel. The best part is, it’ll be cheaper than a mechanic, and you’ll have the tools forever!

Unfortunately, holding the spark plugs into place in any alternative fashion won’t work. They need to be secured into the hole as intended in order to function properly. 

Get Ready

The first thing you’ll need to do is remove the spark plug. You should see the stripped threads in the hole. Clean the damaged threads with the help of your tapping tool.

To avoid too many aluminum shavings from shooting about while you are re-tapping the threads, simply grease up the tap. Greasing is critical because if the aluminum gets inside the engine, it can cause serious damage. 

Get Set

Now stick the tap inside the hole and turn it to start cutting the new threads. Turn it slowly in order to cut the threads. This is so you don’t break anything inside the hole.

When you start drilling and cutting the new threads, use the old ones as a reference to get the alignment right for when it’s time to place the threads back inside.

Thread the tap into the hole. You should be cutting slightly oversized threads. Next, you want to tighten up the tap in the remains of your old spark plug threads. 

If the new threads are parallel to the old ones, then you’re on the right track. It is crucial that your new ones are placed over your old ones for the spark plug to fit into the hole correctly. If you can just take the tap out, then we’re almost done!

And Go

Lastly, you will just screw the thread insert into the mandrel and tighten it. Clean the area of any grease, then just screw in your new spark plug and you’re all set!

Just be sure to clean up your tools when you’re done. Do this every time, and they’ll last you!

Keep up With Those Repairs

Car maintenance is a nightmare sometimes, but if you have the right tools and knowledge on your side, then it can be a lot easier, and even fun!

Now that you know how to fix a stripped spark plug hole, get to work, and learn more about what E-Z LOK™ (Solid Wall) threaded inserts can do for you!