How to Spot FakesTips

How To Spot Fake Denso Iridium Power Spark Plugs 2017

denso9 (Copy)

Err But They Look Identical I Hear You Say?

Just when we thought the counterfeit NGK Spark Plugs we found recently were a pretty close match to the real thing, we’ve now found counterfeit Denso Iridium Power Spark Plugs as well. Every detail has been cloned to the closest result possible, except for one major flaw; these plugs don’t actually feature any Iridium in the center electrode at all!

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Alarm Bells

    • Alarm Bell 1: No laser-welded Iridium tip, features a machined down nickel alloy tip instead.
    • Alarm Bell 2: Low-resolution, scanned copy of the box.
    • Alarm bell 3: Major blooper – EAN of the 4pc outer plug box is stamped onto the 1pc inner boxes.


Below: The same EAN barcode for a 4 quantity plug box has been printed on all of the 1x plug boxes inside, which is completely wrong. Real Denso plugs use a different EAN for a 4pc box and 1pc box. Notice how sharp the real Denso box printing is?

Below: Another telltale sign is the print quality. It seems like a pretty decent scanner has been used, however it’s in no league compared to a print job that’s fresh from the original artwork file.

Below: On the 1x plug boxes, the font is different and the part number is followed by a #4 which indicates 4 pieces (except it’s a 1x plug box, right?)

Below: The cardboard material used is a cheaper type on the fake box. Also look at the corrugated fold lines too, they have a different patterns.

Below: Subtle differences again, printing sharpness, also notice that the curved edge on the thumb flap is a different shape.

Below: Printing sharpness

The Plug

This is where it gets hard to tell them apart. There’s no doubting that these are high quality copies, however to trained eyes and with genuine Denso’s on hand from our stock, the differences are fairly obvious.

Two Below Pics: The centre electrode tip definitely don’t feature a laser welded iridium tip, they appear to be made of a nickel alloy instead which has been machined down.

Below Pic: The crush washer is almost identical, however by looking at the centre recess you’ll notice the genuine Denso has a much deeper groove between the top and bottom rings. The metal areas around the punch letter stamping appear more swollen than the real plug also.

Below Pic: Font style on the part number is very authentic looking, this is a clear sign of tracing paper being used and then transferred to Photoshop for touch up.

Update: August 2018

During the last month or so, Denso has gradually started phasing in a new Iridium Power packaging design. The boxes below are 100% genuine, directly from Denso.

Please share this article as much as possible to make others beware!

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Article Rating: 5


  • Denso iridium IK20 5304 X 6, I have just received my 6 plugs, I did the comparisons on your “how to spot a fake”.
    They seem to be genuine going by your pics.. & comments. Replacing my plugs on a V6 engine with 3 plugs facing the firewall is a mammoth job on my car.
    My question is… Say my plugs are fake, do you have any idea as how they will perform / last ?
    For an integral part, how do these people get away with this ?
    Love your articles.

    • Hello Sam,

      Glad to know the article helped!

      In general, fake plugs are manufactured based around their exterior appearance, so the materials used are really their downfall. In a manner of speaking the quality of the metals used can be comparable from say stainless steel vs mild steel. If you take a look at the fake plug in our article, you’ll see the ‘iridium’ center electrode is in fact nickel. Traditional standard spark plugs feature a nickel center electrode, however they are much larger in diameter, and there’s a reason for that: Lifetime. Now reduce the diameter of that nickel electrode to a 0.7mm tip and you have a spark plug that will probably last only a couple months until the gap is too big and bad running ensumes.

      Individuals who sell fake spark plugs on marketplaces outside of the source country certainly don’t get away with it for long, as long as it’s reported accordingly (which is exactly what we do). As for the source to be taken out, the problem is that there’s no way to enforce a copyright law from one country to the other. Unfortunately for legal reasons we can’t say any more on the matter.

      Hope this helps.

      Best Regards

  • Hi Driven2a

    I recently bought a set of IKH24 Iridium Power spark plugs and my box looks nothing like the one in your pictures.
    Should I be worried? Can I send you some pictures for review? Perhaps Denso is using a new package.

    The printing looks high quality, but the EAN barcode looks more like your fake pictures above than the real Denso ones.
    I am scared to open up the package and feeling inclined to return them alltogether, but would hate to be overreacting. Denso on their part doesn’t seem to answer to consumer inquiries much…

    • Hi Chris,

      No problem, please check your email to reply and send us some photos.

      Also to note, Denso has just released new box artwork for the Iridium Power range. Have a look at this quick photo snap of our latest stock to see what they look like.

      Best Regards

  • Hi thanks for the article. I found myself in the position of counterfeit NGK iridium Platinums. They were misfiring and fouled within a week. High quality copies that, in some aspects, did a better job than the real ones.

    I did several tests to confirm. One involved close look using a 20x magnification with a 5x over that. But after becoming interested in lithium ion 18650 batteries (huge counterfeit market), I came to realize the prints on the boxes can vary. And the plugs.

    This is because the companies have factories in multiple countries, china included. Most distributors are buying wholesale and can’t check every single box. Grade A would mean no defects off the assembly line, B grade might have cosmetic.

    I did ohms resistance test using 4 multi meters 2 of which were $200 Klein cl450 and a UEI379. Results were interesting. I’d like to share with you if you’d be interested, email me.

    One other definitive way I found resolution was using a magnet. Platinum (in my case) is non magnetic. However, Iron and nickel are magnetic!

    Also emailed NGK who confirmed my thoughts as well. Then I started looking at my Denso iridium plugs. Old style power box vs the new and even after speaking to their technical service, I’m left still confused! They’re unwilling to divulge information, which I understand, but really? … Friends thought I was a crazy up until I showed them with a magnet.

    Bought NGK plugs off a 4.5 star Amazon prime seller who got stiffed by their supplier after a year or so of selling genuine. I saved about $15 only, but hey, I got free next day shipping 🙂 never again!

    Article Rating: 5
  • Hello,
    since i want to buy also some iridium spark plugs, i was wondering if Driven2a could give me an opinion for these Denso SC16HR11 looks ok, or suggest if i should ask another picture from the seller. Here the link:

    Thank you.

    ps.these are not in your shop listed.

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