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 centre electrode at all!

Related Articles:

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: EAN of the 4pc outer plug box is stamped onto the 1pc inner boxes. This should be a different EAN number.


Unfortunately, we can’t rely on the packaging as a 100% counterfeit measure. This is because Denso has factories all over the world and undoubtedly each facility will use a different machine for all aspects of the packaging. However, what we can do is look out for clear blooper signs. For example the fakes we discovered had the 4pc EAN number as printed on the outer box, printed onto the 1pc inner boxers too. This kind of mistake would be impossible with Denso’s manufacturing quality control and would mean they’d have no stock figures on 1pc boxes. You can also see the printing sharpness is a lot less in the photo.

It seems like a high quality scanner has been used, however it’s in no league to a print job that’s fresh from an original artwork file.


Below: On the 1x 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? (another blooper)


Below: The cardboard material used is a cheaper type on the fake box. Also look at the corrugated fold lines too, they have 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. You can purchase genuine Denso spark plugs from our online shop. We’re a UK based company however we can provide worldwide shipping.


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: Longer lifetime. Now, by reducing the diameter of that nickel electrode all the way down to just a 0.7mm tip, you have a spark with a far shorter lifespan.

      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 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 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.

  • Hi,

    I really need your help. I bought my Denso Iridium Tough VT20 online. I am from Malaysia. I am not sure whether it is original or not. I try to scrape the letters on the spark plugs, and it remains intact. Can I send you some pictures for you to help me verify the authenticity?

  • It is great article. We cannot really rely on the box but obvious box misprint is a good sign. Unlike in USA with many local stores (Advaced, Autozon, Napa, etc.), there is almost no local store in Germany. Only Manufacturer Stealership or Online seller. I am not sure if we even can buy Toyota Dealer part directly which is rebadge Denso. I bought SC16HR11 which is updated version of Toyota Corolla/Auris or Prius with 1.8L Hybrid engine from *link removed*. It cost about €10 each, and 4 plugs box has different barcode than individual box. The color match genuine Denso but the ground soldering is not smooth like NGK Iridium Platinum laser ground electrode. Unfortunately, NGK version has colder range, similar to SC22HR11 that may cause issue for not hot enough and keep the tip clean.
    I would like to see the ground electrode on the genuine Denso Iridium in general, thanks.

    Article Rating: 5
  • I’m totally paranoid now. I just got some for my race car, but if these are fakes it could ruin my race. Not sure if these are real or not.

    Article Rating: 4
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