Spark Plug Failure Cause

The #1 Cause of Spark Plug Failure

Many factors can cause a spark plug to fail; from incorrect heat ranges to improper gapping, to chemical contamination.

Sponsored by NGK Spark Plugs

Many factors can cause a spark plug to fail; from incorrect heat ranges to improper gapping, to chemical contamination. Yet 90% of spark plug damage claims are due to improper torque. Proper installation torque is critical in the plug’s ability to dissipate heat out of the combustion chamber and into the cylinder head. Not using a torque wrench when installing plugs can lead to over-torquing or under-torquing a spark plug, which will cause damage to the plug and possibly the engine.

It’s critical to follow the manufacture’s torque specifications when installing a plug. Make sure to use a torque wrench that corresponds to the torque specified on the packaging of the spark plug. Specifications vary by seat type, thread diameter and cylinder head types; so make sure to account for these three factors when installing a plug. The difference between an over-torqued or under-torqued spark plug, is often using an incorrect tool or not using one at all.

Engine Damage from Insufficient Torque

An under-torqued spark plug will not make full contact with the cylinder head. This reduces a plug’s ability to transfer heat and will result in elevated combustion chamber temperatures. Such temperatures can cause pre-ignition and detonation and lead to engine damage. Excess vibration and subsequent damage to the ground electrode and terminal nut may also occur. An over-torqued spark plug can cause stress to the metal shell, leading to thread damage or breakage. Over tightening can also compromise a plug’s internal gas seal or even cause a hairline fracture in the insulator. Such damage results in problems similar to an under-torqued plug: improper heat dissipation or exhaust gas blow-by.

Thread Damage from Excessive Torque

In addition to using the correct torque wrench, take care to clean the area around the spark plug hole with compressed air and make sure the plug thread is free of lubricant and carbon build-up. Torquing against debris and build-up around and on a spark plug prevents the plug from making full contact with the cylinder head, even if a torque wrench indicates otherwise. Secondly, avoid using chemicals during installation. Refer to the manufacturer’s recommendations on use of anti-seize, as it’s not recommended for all plugs and may cause thread shell damage. Lastly, make sure the engine is cool before installing or removing a plug to avoid damaging to the cylinder head.

Remember anything interfering with the torque process can cause a plug to fail or worse, engine damage.

For more information or questions about installing spark plugs you can reach out to the NGK Technical Support line by calling 877-473-6767 or visit them on the web at www.ngksparkplugs.com.

You May Also Like

Warn Your Customers About Water Pump Failure During the Summer

Summer is an opportune time for automotive professionals to remind customers to keep an eye on the signs of a failing water pump.  As you know, extreme summer temperatures and added strain on vehicles from activities like long road trips can cause engines to become more susceptible to troubles from excessive heat, making the function

Summer is an opportune time for automotive professionals to remind customers to keep an eye on the signs of a failing water pump. 

As you know, extreme summer temperatures and added strain on vehicles from activities like long road trips can cause engines to become more susceptible to troubles from excessive heat, making the function of the water pump even more critical.

6 Signs It’s Time to Put Down the Pen and Ditch the Paper 

There’s no time to hesitate.  The surge in the aftermarket sweet spot — or vehicles in the six- to 12-year age range that will soon require significant repairs — reached 94 million in the first half of 2021, according to Experian Automotive. That total accounts for nearly 31% of all vehicles in operation.  That percentage

I Have A Website, So Why Do I Need Marketing?

Now that your website is up and running, how can you consistently engage with your customers and always deliver a positive experience? This can be done by taking a multifaceted approach through omnichannel marketing. With a little effort and all the right tools, you can outshine your competition and fill your bays in no time!

Why Brake Pads and Brake Rotors Should Be Replaced Together

Brake pads and rotors should always be replaced in pairs.  Pairing new pads with worn rotors could cause a lack of proper surface contact between the pads and rotors, resulting in noise, vibration, or less-than-peak stopping performance. While there are different schools of thought on this paired part replacement, at ADVICS, our technicians always recommend

Oxygen Sensors – Technology, Types, Evolution, and Life Expectancy

Since the implementation of OBDII, the oxygen sensor has been a main staple of engine management systems. Modern oxygen sensors are much faster and more accurate than their older counterparts. This allows the engine to enter closed loop control faster which decreases emissions and fuel usage by as much as 15-20%.  O2 sensors are separated

Other Posts

Training Techniques to Teach Today’s Techs (VIDEO)

The need, dependency and resources for training continue to grow. This video is sponsored by The Group Training Academy.

Learn To Advise Customers, Not Just Sell Them

Service advisors are a liaison between the tech and the customer. This video is sponsored by The Group Training Academy.

Learn To Advise Customers, Not Just Sell Them

Service advisors are a liaison between the tech and the customer. This video is sponsored by The Group Training Academy.

Benefits of Using Brake Parts Designed to Work Together

When replacing brake system components, it might seem like using compatible parts from any manufacturer – regardless of brand – should get the job done. However, for the safest brake job with the best performance, it’s always best to use parts from the same manufacturer, like ADVICS, where our brake pads, brake rotors, hydraulics, calipers