Top 7 Reasons: Should You Use a Torque Wrench for Spark Plugs? A Complete Guide for DIYers

Image of a spark plug, a vital component in an internal combustion engine, used to ignite the fuel and air mixture in the combustion chamber.

Hey there, DIY warriors! Ever wondered if you need a torque wrench for spark plugs? Fret not, as we’ve got you covered. In this article, we’ll dive into the ins and outs of using a torque wrench for spark plugs, answer some frequently asked questions, and provide you with all the information you need to make an informed decision.

There are varying opinions on the use of torque wrench for spark plugs the decision if up to you but know the risks and benefits before you hand tighten spark plugs . If you have ever snapped the head off of a bolt, then chances are you were applying way too much torque. Ensuring that a threaded component fits tightly is an important part of ensuring the proper maintenance of any vehicle. Although it would seem obvious that a threaded component such as a spark plug should be as tight as possible, over-tightening one can result in damage to the plug itself, or even to the cylinder head.

Why Use a Torque Wrench for Spark Plugs?

Spark plugs are a crucial component of your vehicle’s ignition system. Overtightening or under-tightening them can wreak havoc on your engine. A torque wrench ensures that you tighten the spark plug to the manufacturer’s recommended torque value, improving engine performance and longevity.

Types of Torque Wrenches

There are a variety of torque wrenches available, each with a specific purpose. The most common is the click torque wrench, known for its precision and audible “click” when reaching the set torque value. The beam torque wrench, while accurate, might pose challenges in hard-to-reach areas. The digital torque wrench is the most high-end option, with a digital screen for enhanced accuracy.

You can get torque wrenches in a number of different sizes. These sizes reflect the readily available rachet sets that can be purchased at any hardware store. As a general rule of thumb, when changing your spark plugs, you will use a 3/8-inch rachet. In fact, most standard rachet sets include at least one spark plug socket. Since the amount of torque that is needed to properly seat a spark plug within the cylinder head is between 5 and 7 ft. lbs., there is no need for anything larger than a 3/8-inch torque wrench.

Now, let’s tackle some frequently asked questions!

What Happens If You Don’t Torque Your Spark Plugs?

Let’s face it, not everyone truly loves working on their vehicle. It is a time-consuming task, that often leaves your knuckles bruised and bloodied, not to mention covered with some nasty grease. People are in such a rush these days, that the simple things can be often overlooked. As spark plugs are such a crucial part of the operation of any internal combustion engine, it is important to make sure that they are functioning the best they can.

We’ve all heard stories about someone going to an oil change place, and having an inexperienced technician failing to properly tighten down the drain bolt. As a result, the oil begins to drain out of the bottom of the engine and the motor seizes up a couple of miles down the road. While failing to properly seat your spark plugs will not result in the engine oil spilling all over the city streets, it will result in lower compression ratios and the potential for fires.

An improperly seated spark plug allows air to be pushed out around the spark plug whenever the cylinder moves up to the top dead center position. This is an important point in the combustion process, and it requires a sealed compression chamber. Any leak, such as around the threads of a spark plug, can force fuel and air out of the cylinder resulting and damage to the engine, and possibly even a fire. It can also cause engine misfires and trigger check engine light.

How do I find the right spark plug torque wrench for my vehicle?

To find the right torque wrench for your vehicle, consult your owner’s manual for the recommended torque value for spark plugs. Next, choose a torque wrench that can handle that value and has the right drive size for your spark plug socket.

How Do You Install a Spark Plug Without a Torque Wrench?

While it is not recommended to install a spark plug without using a torque wrench, it is still possible. There are times when you just don’t have access to a torque wrench in order to properly seat the spark plug. In order to determine how much torque, you are placing on the spark plug itself, you will need to calculate it based on the length of the rachet handle. It is much more difficult to determine the amount of torque being applied to the spark plug without using a torque wrench though.

Can You Tighten Spark Plugs Without a Torque Wrench?

Although it is possible to tighten spark plugs without using a torque wrench, it is hard to ensure that you are properly seating the spark plug in the cylinder head. Too little torque can result in a loss of compression, as well as pre-ignition. Too much torque can damage the spark plug or even the cylinder head itself.

When you fail to properly seat your spark plugs, the cylinder will fail to fire properly. This is a result of the fuel and air mixture being compressed by the cylinder as it moved to the top dead center position. It is during this compression, that the spark plug is supposed to ignite the mixture of fuel and air, forcing the piston back down. However, even a slight leak around the threads of the spark plug can reduce the amount of compression substantially.

When you over-tightening a spark plug, it is very easy to strip out the threads in the cylinder head. It is important to ensure that you never over-tighten your plugs because eventually, you will need to remove that spark plug again in the future. If you did not strip out the threads when tightening the spark plug, it is still possible to strip them out when you attempt to remove the spark plug from the cylinder head. This can create a lot of headaches for any vehicle owner.

How Tight Should A Spark Plug Be If You’re Hand Tightening?

Ultimately, it is still possible to hand tighten spark plugs safely. In order to hand tighten a spark plug, you will need to make sure that both the threads on the cylinder head and spark plug are free of any debris. From there, you can simply use your fingers to screw the spark plug into place until the compression washers contact the bottom of the spark plug well. You can also use the spark plug socket to help you with this task. Once you are no longer able to tighten the spark plug by hand further, you can use a standard 3/8-inch ratchet to finish the job, by turning the plug roughly a 1/4 of a turn further.

Decision is up to you to use a torque wrench or not, our recommendation is you do especially if this is you first time changing out spark plugs.

How cheap can I go for a spark plug torque wrench?

While it’s possible to find budget-friendly torque wrenches, be cautious of extremely low-priced options, as they may compromise on quality and accuracy. Invest in a reliable, well-reviewed torque wrench for long-lasting, accurate results.

Our picks based on amazon reviews:

  1. TEKTON 1/4 Inch Drive Micrometer Torque Wrench (20-200 in.-lb.) | 24320 – 4.8 out of 5 stars, 28,160 ratings
  2. LEXIVON 1/2-Inch Drive Click Torque Wrench 10~150 Ft-Lb/13.6~203.5 Nm (LX-183) – 4.7 out of 5 stars, 7,402 ratings
  3. TEKTON 1/4 Inch Drive Dual-Direction Click Torque Wrench (10-150 in.-lb.) | TRQ21101 – 4.7 out of 5 stars, 3,319 ratings
  4. GEARWRENCH 3 Pc. 3/8″ Drive 90 Tooth Spark Plug Ratchet Set – 81229T – 4.8 out of 5 stars, 52 ratings
  5. CRAFTSMAN CMMT99433 3/8-IN Drive Torque Wrench – 4.8 out of 5 stars, 865 ratings
  6. GEARWRENCH 3/8 Drive Electronic Torque Wrench 7.4-99.6 FT LB – 85076 – 4.7 out of 5 stars, 1,989 ratings
  7. DEWALT Torque Wrench, Micro Adjust, 3/8″ Drive (DWMT75463) – 4.8 out of 5 stars, 413 ratings
  8. Summit Tools 3/8 inch Digital Torque Wrench, 1.11-22.12 ft-lbs (1.5-30 N-m) Torque Range, Sequential LED and Buzzer, Socket Set, Calibrated (WSP3-030CN) – 4.6 out of 5 stars, 361 ratings
  9. Teng Tools 1/2 Inch Drive 30 to 150 FT-LB Reversible Click Steel Torque Wrench – 1292UAGEP – 4.7 out of 5 stars, 201 ratings
  10. Neiko 20743A 3/4”-Inch Digital Torque Adapter, 150-750 ft-lb, Digital Torque Wrench Converter/Torque Wrench Adapter, Alerts Torque Setting, Calibrate Digital and Analog Torque Wrenches – 4.5 out of 5 stars, 1,433 ratings


In summary, using a torque wrench for spark plugs is highly recommended but not strictly necessary. It ensures proper tightening, preventing engine damage, and enhancing performance. We hope this article has provided you with the information you need to make an informed decision on whether or not to use a torque wrench for spark plugs. Now go out there and keep your vehicle in tip-top shape!

If you’re looking to learn more about how to use a torque wrench correctly, check out this helpful article from Popular Mechanics:

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