How Tight Should Spark Plugs Be To Avoid Damaging Your Engine?

Spark Plugs

The tightening of spark plugs changes according to the diameter of a particular spark plug. The issue that matters is how correctly should one install or remove the spark plugs.

Doing the installation as well as removal of the spark plugs correctly help one to avoid performance problems, hours of hassle, cylinder head damage and much more.

Installation And Removal Of Spark Plugs

Spark Plugs

Over tightening the spark plugs or just improperly cleaning your threads in the cylinder head prior to installing your new spark plug is a common problem that can result in thread damage. Undermining these small issues can lead to breakage problems in the next replacement.

Another problem is the thread galling in the aluminum cylinder heads. Binding or galling between the plug and the head can end up destroying the thread and result in plug breakage. It is important to allow the engine to cool before trying to uninstall the spark plug.

The installation recommendations differ by the design of the spark plug. However, ensure there is no carbon or just other contamination in your cylinder head threads before the installation process.

There are unique tips that are designed to clean your threads as well as remove residual carbon when necessary. Also, make sure your threads on your spark plug are not damaged. Never install a spark plug that has been dropped even if it was a new spark plug.

Spark Plugs

Generally, spark plugs are pre-gapped when they are new. However, it is important to verify that the spark plug gap meets your car’s manufacturer’s recommendation for the specific recommendation you are dealing with before you install the spark plug into your engine.

The tapered seat spark plugs must be installed by the use of the hands until finger-tight. Use an extra 1/16th turn with a spark plug wrench to make sure your spark plug is tightened to the manufacture’s recommendation.

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Also, you can use a torque wrench to tighten the spark to approximately 7 to 15 lb. ft. for 14mm threads and 15 to 20 lb. for 18mm threads to make sure a gastight seal. Hence, overtightening a spark plug might stretch your plug body and result in breakage when removing it.

For the gasket-kind plugs, always install the plug until finger-tight. In case the plug is installed with a new gasket, utilize a spark plug wrench so as to apply 3/8 to 5/8 turn which depends on the head material. When you install a used spark plug with also a used gasket, use a ¼ turn regardless of the head material.

The Hard Job: Plug Removal

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It is normal to have some difficulties in removing a used spark plug. Make sure you allow your engine to cool before starting the removal process. Always ensure to clean away all the debris within the plug before you remove it or use compressed air that prevents debris entry in the engine.

If the plug is tightened hard or there is some corrosion that surrounds its base, it is advisable you apply some penetrating oil. After allowing oil to do its work, apply a steady pressure on the spark plug wrench till your spark plug gets loose. Never yank on the wrench to avoid breakage.

Try loosening ¼ turn as you retighten. Repeat the procedure as you reapply penetrating oil until you remove your plug.

It is a good idea to utilize a thread chaser tool in removing the carbon as well as other contaminants that are on the threads before you install a new spark plug.

Tips And Warnings On Changing Your Car’s Spark Plugs

Spark Plugs

  • Take a careful look at the service procedure that is recommended by your car manufacturer and ensure all the necessary tools and parts are available. Some engine platforms need removal of the upper intake manifold to get the access to your spark plugs. Special tools, as well as additional gaskets, might be needed.
  • Allow your engine to cool down. Removing the spark plugs from when the engine is hot may force the spark plug threads to end up seized, resulting in damage to your cylinder head threads.
  • Remove your spark plug boots by initially twisting your boots back and forth till they start moving freely on the spark plug. Then pull off as you hold your spark plug boot. Label your wires to make sure they are reinstalled correctly.
  • Forcefully pulling your spark plug boot can cause the spark plug wire end to pull out and it will require replacing the spark plug wire.
  • Clean your spark plug before removing your spark plug. If you fail to do so, you may damage your engine since the dirt or the foreign material that enters the cylinder head. The contaminated threads prevent proper seating of your new spark plug.
  • In case the spark plug is hard to unthread, stop and use a penetrating lubricant and let it soak for five minutes. You can then tighten your spark plug back up and remove it again. It is necessary to follow this process various times until your spark plug is finally removed.
  • It is advisable to use only hand tools in removing and installing your spark plugs to avoid damages to the spark plug or the cylinder.
  • Utilize only spark plugs that are specified by your car’s manufacturer. Never use cold or hot spark plugs. Installing the spark plugs of another kind or heat range can result to bad damages to your engine.
  • Check the gap of the new spark plugs prior to installing them in your engine. Installing the spark plugs having the wrong gap can result in very poor performance and can even destroy your engine.


Spark Plugs

How to the spark plugs should be, depends on the type of vehicle you have. While installing the spark plugs it is recommended you check the recommendations offered by your car’s manufacturer so that you may know the right type of spark plugs to use and how tight they should be.

Categorized as Maintenance

By Stella Grant

My name is Stella Grant. I am atrained mechanic with years of experience. Thanks to years experience I have plenty to share on auto maintenance and am willing to help you make your automobile work smooth – from the inside out.

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