Torque Wrench for Spark Plugs: The Right One for the Job

A torque wrench for spark plugs is the most accurate device to help you properly fix a spark plug in the cylinder of an engine. Since they come in different options, it can be a mountain climb to determine which is the perfect one, especially if you are a beginner.

Torque Wrench for Spark Plugs

Fortunately, we’ve come up with this guide to help you decide which torque wrench to use and how to use it to change spark plugs. This article will also discuss the importance of torque wrenches and other available options you can use to change the plugs.

Which Torque Wrench for Spark Plugs Is Recommended?

The ⅜ torque wrench for spark plugs is highly recommended for most vehicles. However, there are a few that these recommended torque wrenches may not be able to fix. Thus, you’ll need to consider the type and size of the torque wrench as well.

A torque wrench is a tool that is used to fasten bolts, nuts and lag screws by applying a specific torque. It resembles a socket wrench but features a scale that indicates when the right torque has been achieved during its use. Others use an internal mechanism instead.

You need a torque wrench to ensure the spark plugs are perfectly tight. However, if you don’t have a spark plug, you can use your fingers but ensure that the plug is not too tight or slightly loose.

– The Various Sizes of Torque Wrenches for Spark Plugs

There are four main sizes of torque wrenches, and each size is used for fastening different bolts or nuts. The four sizes are ⅜ inch, ¼ inch, ¾ to 1 inch, and ½ inch. For work on a car’s spark plug, most vehicles will require either ⅜ inch or ½ inch. Working on the spark plug of a moped or a motorcycle will require a ¼ torque wrench.

Changing tires requires a ½ inch wrench while a ⅜ inch wrench is suited for tightening bolts found in car engines. For bigger cars such as those used in construction works, a ¾ to 1 inch torque wrench is the best.

– The Importance of Spark Plugs

Spark plugs are the reason your engine can start and the car can move. This is why you need to pay close attention and constantly check to ensure that they are in good condition. The spark plugs work by sending a bolt of electricity between a small gap at the top. This action ignites the air/fuel mixture in the cylinder and gets the piston moving to complete the combustion process.

The Importance of Spark Plugs

A faulty spark plug may not ignite the air and fuel mixture or even send a delayed spark, which may cause the engine to misfire. Experts say that spark plugs should be replaced between 30,000 miles to 50,000 miles to ensure they function properly.

What Are the Different Types of Torque Wrenches for Spark Plugs?

The different types of torque wrenches for spark plugs are click torque wrenches, beam torque wrenches, and electronic torque wrenches, with each one having their own advantages. Torque wrenches come in different types and sizes; each designed for a specific purpose. 

– Click Torque Wrench 

Also known as the clicker, it is the most common type of wrench used for spark plugs and it comes in different sizes. The force applied on the clicker can be adjusted within a given range using a clutch mechanism. This type of wrench makes a sound when you reach the right torque that was set. To set the clicker, you need to adjust the spring-loaded lever by twisting the handle until you get the desired result.

Click Torque Wrench

The clicker is regarded as the most accurate because of the sound it makes when the job is done and it is also very cheap, considering its accuracy. Finding the best setting can be challenging, but some experts recommend setting the clicker torque to 7 ft-lbs.

– Beam Torque Wrench

A beam torque wrench is also accurate and can do the job if only the right torque is set. The tool has two beams: one moves following the force applied on the torque when the handle is adjusted while the other remains undeflected and serves as an indicator. When you set the torque wrench to the right value as indicated by the car manual, it’ll fasten the car plugs just right. 

Though the beam torque is accurate, it can be a bit awkward to use when the spark plugs are on the backside. It is best for designs where the spark plugs are placed on a tiny motor or cylinder.

– Electronic Torque Wrench

These spark plug torque wrenches are expensive and are mainly used at mechanic shops. The torque wrench features a digital display that gives the most accurate reading compared to the other two types.

Electronic Torque Wrench

The digital torque wrench for spark plugs is the best for amateurs who may have difficulties reading or setting the torque values using the other two torque wrenches. However, its costly price means that only repair shops can afford it.

How Can You Use a Torque Wrench To Fasten a Spark Plug?

To use a torque wrench to fasten a spark plug, you have to first gather the right materials. Next, clean the ignition component and carefully remove the spark plugs. Install the new spark plugs after that and you’re done! Make sure to handle everything with care to prevent unwanted costs.

How tight should spark plugs be torqued? Sparks plugs should be tightened with the finger until the plug gets to the gasket head, then use the torque wrench to further tighten it around ½ – ⅔ turns.

The manual will indicate the right torque to fasten a spark plug, but how to use a torque wrench for spark plugs can be a bit tricky. We recommend that you take the vehicle to a mechanic shop for assistance. However, if you are low on funds and would want to save some money, then this guide should help you navigate the process.

– Make Sure You Have the Right Materials

The first step is to ensure that you have the right materials for the job. The materials for this job include a torque wrench, spark plug, gauge cap, and ratchet.

You should also be dressed in protective clothing whenever you’re working on your vehicle.

– Clean the Ignition Component and Remove the Spark Plugs

Once everything is set, open the ignition coil area and clean it with an air duster to ensure no debris or speck of dust is in the component.

The next step is to take out the ignition coil and the connector on top of the spark plugs then remove the spark plugs

– Install New Spark Plugs

To install the new spark plugs, check the manufacturing guide to know the correct spark plug gap and adjust accordingly. Then fasten the spark plug with a torque wrench, but be sure to do it gently so you don’t break the delicate parts. Each torque wrench is operated differently but the results are all the same if you use them according to their guidelines. For example, to use the beam torque wrench, loosen the thumb screw and set the correct torque value on the sliding scale.

Install New Spark Plugs

Then tighten the thumbscrew and push in the indicator pin to secure the torque value you just set. Fix the ½ inch square drive and the required socket then firmly grip the handle of the torque wrench to hold it in place. Now, pull the handle slowly until you hear the click sound and see the indicator pin pop out. Do not apply force after you hear the click or this would cause the fastener to break.

Make sure not to tighten the spark plugs too much. If the spark plugs are too tight, the ignition can develop several issues like high-stress load on the ignition system. The housing of the spark plug could be damaged, causing the thread to break. A spark plug that is too tight will not function properly and will have to be replaced. 

How about loose spark plugs? A loose spark plug may lead to several ignition problems including engine misfires, delayed acceleration, unstable spark plugs, a dead cylinder, pre-ignition problems, and an unresponsive engine. This is why you need the right torque to keep the spark plugs in place.

Can You Fasten Spark Plugs Without a Torque Wrench?

Yes, you can fasten spark plugs without a torque wrench, but the disadvantage is that you’re likely to fasten it too tight or slightly loose. The best tool to use is the torque wrench, but in its absence, you can rely on your judgment to do the trick.

On how to tighten spark plugs without a torque wrench, just place the spark plugs at the top of the cylinder head and use your fingers to screw them into place. Turn the spark plugs until it is tight enough. You can later use the torque wrench to check if it is perfectly tight and adjust accordingly.

Take note that although you can use the torque wrench to loosen bolts or nuts, it is not advisable to do so because the tool is not designed to perform such tasks.


So far we’ve determined the best torque wrench for spark plugs, discovered how to use it and why spark plugs are important.

Here is a summary of all that we’ve read:

  • The best way to install a spark plug in an engine is via the use of the torque wrench designed for spark plugs.
  • The torque wrenches designed for spark plugs come in three types: beam, electronic, and click.
  • The click torque wrench is the most accurate as it gives off a clicking sound immediately after the right torque is attained.
  • The best torque wrench size for spark plugs for vehicles is ½ inch or ⅜ inch while bigger vehicles use the ¾ to 1 inch torque wrench.
  • Loose spark plugs can result in several engine issues including misfiring, unresponsive engine and delayed acceleration, while an overtightened spark plug could cause it to break.

You can use your hand to tighten the spark plug until it reaches the head gasket then you can use the spark plug wrench to tighten it to the right torque. Ensure you change the spark plugs after 30,000 miles to 50,000 miles to maintain a healthy engine.

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