NGK Iridium spark plug original vs fake

I figure I would put a little PSA out there about identifying fake NGK spark plugs. There is already information out there, but some of it is outdated as these clowns try to make a better copies (in looks, not performance). This is a comparison between TR5IX plugs I picked up on eBay for $38 shipped and plugs I bought at Advance Auto for $54 after a $5 rewards coupon and a 25% discount. So, the price difference isn't that drastic. Here is the ad on eBay:

NGK Iridium spark plug original vs fake

For anyone who has spent ten minutes on the internet before, the ad does look suspect. Typically, anything that is advertised as "USA shipping" or puts the word "For" in front of the item your looking to buy should be avoided. However, as you will see, they did use real NGK plugs for the pictures. It should be noted that these plugs are also sold on Amazon.

The sad thing is that the average person isn't going to have another set of NGK plugs to compare the fakes against, and if you just have these plugs in your hands, you may not know the difference. However, the subterfuge disappears quickly when you do have a real set to compare against. For the following pictures, the real NGKs are on the left and the fakes are on the right.

The logo is much larger and the entire box is much brighter on the left. Notice how the spark plug on the fake box has a blue tint to it, and the color transitions aren't nearly as defined:

NGK Iridium spark plug original vs fake

The dead giveaway is the letter spacing of the model number. The real box has the letters much more condensed and the fakes have gaps that you could kick a field goal through. The "NGK" is a much brighter red on the real box, and the bar code itself is larger. The font for "Iridium IX" is also different.

NGK Iridium spark plug original vs fake

The back of the boxes show further distinctions. The fake box's white background looks like an undershirt that was never separated for laundry day. The wording in the bottom right is completely different, as well.

NGK Iridium spark plug original vs fake

Stark bar code differences, and the real box's colors are much brighter with the transitions much more clearly defined.

NGK Iridium spark plug original vs fake


NGK Iridium spark plug original vs fake

The smaller plug box is no different, with the fake plug completely washed in blue.

NGK Iridium spark plug original vs fake

The same letter spacing carried onto the smaller box. Notice the letter spacing in the ad's pictures matches the spacing of the real NGKs.

NGK Iridium spark plug original vs fake

Bar code and font differences. Again, not something you would pick up on without having a real version to compare to.

NGK Iridium spark plug original vs fake

More subtle differences.

NGK Iridium spark plug original vs fake

Onto the plugs themselves. The cardboard sleeve isn't a dead giveaway as I has just installed some TR6IXs from Advance in the GTO, and they had cardboard sleeves. However, the printing is definitely much more distinct on the real plug. Also, NGK has replaced "NGK Japan" on the hex with "Assembled in the US from Japanese parts."

NGK Iridium spark plug original vs fake

The plug ends on the real NGKs are definitely a higher quality with much better defined transitions.

NGK Iridium spark plug original vs fake

True NGKs have a noticeable dimple, whereas the fakes do not:

NGK Iridium spark plug original vs fake

Here is where things get critical. Look at the difference between the true NGK iridium tip and the fake iridium tip. One of the major benefits of iridium plugs is the narrow electrode. I would also highly doubt that the tip is actually iridium. Another critical difference is the length of the ceramic insulator. Both plugs are supposed to be the same heat range, but the fake's insulator length would suggest that it is a colder plug than a true TR5IX. It looks like it could be a heat range of 6 or possibly even 7. Further down, you can see the difference in quality of the thread cuts and the taper seats.

NGK Iridium spark plug original vs fake

The ground electrodes are completely different in shape and size, as well.

NGK Iridium spark plug original vs fake

Where the ceramic inserts into the hex, you can see the real NGKs have a powder whereas the fakes have a sloppy sealant of some sort. The sloppiness wasn't on all of the fake plugs, but the powder wasn't on any of them.

NGK Iridium spark plug original vs fake

So, there is my comparison between the two. I've seen a couple videos and other posts highlighting differences, but I figured I would add to the collection using plugs that I acquired in 2021. Having just the fakes in your hand, not many people would know the difference. Hopefully, this will help people verify if their plug is authentic or not. I would say that your safest bet is to get your plugs from a trusted source such as Rock Auto, Advance, O'Reilly's, etc. However, I would still caution to double check the plugs you get, because I wouldn't put it beyond someone to buy real plugs and return the fakes just to have the parts store toss them back on the shelf for the next person to buy.

How can you tell a fake NGK?

5 Signs That Your Spark Plugs Are Fake.
Look at the top of your spark plug. There is a slight hollow in the top of NGK spark plugs. ... .
Check your spark plugs' threads and stamps. ... .
Check the alignment of the brand name. ... .
Check for a number on the hex nut. ... .
Look closely at the packaging..

What happens if you use fake spark plugs?

With poor ignition causing poor fuel economy and poor engine start up, the fake spark plugs' low grade composition causes them to overheat quickly. Drivers will notice a major drop in engine power, particularly under heavy acceleration or load.

How much is an original iridium spark plug?

Why Iridium Spark Plug is expensive and is it worth it? This precious material costs more than $5,000 per ounce, which means that it is the most expensive material used in spark plugs production.