Authenticity of DENSO Iridium TT

You may have gotten fakes, don't get surprised or too angry, sh1t happens. RA is a reseller after all.
i got many parts from RA and all seemed at least real and work great including spark plugs and Denso (in buddy's RAV4) while different part number - that paint bleed in the name looks wrong...
 
What would that look like, where should I look? There are some codes on the box but I don't know how to read them. Box says copyright 2014.

The 9BD stamped on the flat in a couple of the pics is almost certain to be the date code.

If I had to guess: 2019 / B=Feb / D=4th week.

Since they came in a box of four, the chances are higher they should all be from the same batch, and have the same code.

I did a cursory search for a packaging or paper company with a logo like that on the box flap, but didn't come up with anything.

I still feel they're authentic, based on my research for new plugs (which affirmed my preference for NGK's fit and finish), but that's just a feeling. It would be troubling if fakes have entered the specialty supply chain.
 
I had to remove counterfeits from my Tundra as well as my Tacoma. They were NGK knockoffs. Both were shot in under 30,000 miles. I called NGK and they confirmed fakes by the code stamped. Lesson learned to only buy from authorized reseller. I avoided a disaster.
 
I bought DENSO Iridium TT plugs from RockAuto, part 4704, DENSO part IKH20TT. I am not overly impressed with the quality of them and have doubts about their authenticity. I emailed DENDO and they say RockAuto is not an authorized dealer. Seeing as RockAuto is a reseller, it is possible they have inadvertently resold me counterfeit parts.

There is a lot of info online about counterfeit DENSO plugs.

Things that appear authentic:
I have tried scratching the ink off the ceramic, it's baked on correctly
I have tried scratching the metal, it seems to be a quality alloy and not cheaply plated
The electrical tip appears genuine according to the various DENSO spot a fake guides
The box appears authentic, good quality printing, bar code seems ligit etc

Things that appear fake:
They have "ASSEMBLED IN US WITH FOREIGN CONTENT" stamped on them rather than "DENSO +++++++" not great quality stamping
The center ground electrode on some appears to be on a slight angle
The printing on the ceramic is slightly blurry in places and not as crisply printed as I'd expect.

Perhaps DENSO has a USA factory, and perhaps it produces a lower quality appearing product than the Japanese factory. As long as it works as well, I don't care. Given all the hype about the precision of the gap and special metals used to improve performance and longevity, the angled electrodes seem to be sloppy manufacturing and negate some of the alleged benefits of the precise tips used.

Compared to Bosch plugs I've bought in the past, these appear very cheap. I was under the impression DENSO was a high quality product and if these are genuine, I'm surprised DENSO would lower their standards.
i sold what supposed to be original denso at AAP,i don.t recall any issue with counterfit. but the original plug was at best 7 out of 10
 
I have Densos in my Mustang. Needed colder plugs (Roush Supercharger) and the Densos came pregapped to the correct gap. Mine are not the exact same plug but also don't have the bump on the ground electrode.
 
I’ve bought 6 plugs, same part #, from Canadian Tire, which is an authorized dealer. They have different codes stamped on them but after looking closely, I’m second guessing if the Rock Auto purchase ones are possibly genuine. They look quite similar, possibly from same production line but different runs.

The RA plugs shipped from an address that belongs to an authorized dealer, as noted in my previous posts. The packaging (often cited as a method of identifying counterfeit) looks identical. Doing a “scratch test” on the ceramic and metal body has identical results. Both sets have fairly poor resolution printing of “IRIDIUM” on them, look about the same. Threads , metal body and electrical connector on the end look identical.

RA bought plugs have “9BD” on them. 4 of my CT bought plugs have “1KC” and 2 have “LGC”. Those 2 had cardboard covers over the tips, all others had plastic covers. RA plugs have a somewhat blue colour to the center electrode, but only under certain light. CT plugs look more blue. RA plugs have “ASSEMBLED IN THE US WITH FOREIGN CONTENT”, while the CT plugs have “ASSEMBLED IN USA WITH JAPANESE & US PARTS”, both sets have fairly low quality standings, not nearly as nice as the normal “DENSO JAPAN +++++”.

I have requested a return shipping label from RA and have to ship them soon if I decide to send them back.

CT bought plugs come to $79.19 (Canadian $) all in. RA bought plugs come to $68.34. There’s a $20 cost to return RA plugs. Basically it’s a $31 decision to use the CT sourced parts at this point. Thoughts?

Pics to follow....
 
Last edited:
These are RA bought plugs. The pic of the single plug is probably the worst of the lot, center electrode is the most crooked
 

Attachments

  • 3BD6B5EB-FFE4-4768-A096-7968B82068B1.jpeg
    3BD6B5EB-FFE4-4768-A096-7968B82068B1.jpeg
    171.9 KB · Views: 124
  • 63018DF6-98D1-45D0-ABFD-162CC3304E0A.jpeg
    63018DF6-98D1-45D0-ABFD-162CC3304E0A.jpeg
    187 KB · Views: 107
  • 9BD4DEA8-755B-4E5D-A4A6-F27FD1D45E1A.jpeg
    9BD4DEA8-755B-4E5D-A4A6-F27FD1D45E1A.jpeg
    227 KB · Views: 102
  • 6C47D950-688F-42B4-BA56-84075AACF457.jpeg
    6C47D950-688F-42B4-BA56-84075AACF457.jpeg
    197.1 KB · Views: 119
  • B16B8413-BD71-4BCA-BB21-C7454D41C171.jpeg
    B16B8413-BD71-4BCA-BB21-C7454D41C171.jpeg
    196.3 KB · Views: 125
These are the CT bought plugs. They generally look better, center electrode straighter (but not as good as I’d expect) and more obvious blue colour.
 

Attachments

  • 365F3DB3-E9B0-4F6D-85AD-B1E2959187E2.jpeg
    365F3DB3-E9B0-4F6D-85AD-B1E2959187E2.jpeg
    222.5 KB · Views: 86
  • CEED3C5C-71E4-437C-A400-C94A74F78F27.jpeg
    CEED3C5C-71E4-437C-A400-C94A74F78F27.jpeg
    231.1 KB · Views: 85
  • 0D12F898-6A46-4D8D-87EA-3C846D7A6FCE.jpeg
    0D12F898-6A46-4D8D-87EA-3C846D7A6FCE.jpeg
    234 KB · Views: 78
  • 23305B61-49F1-407F-8C10-0D41E3680EB8.jpeg
    23305B61-49F1-407F-8C10-0D41E3680EB8.jpeg
    228.1 KB · Views: 78
  • B9C77D9A-2A30-4FC7-B5B4-E9CE2E4282A5.jpeg
    B9C77D9A-2A30-4FC7-B5B4-E9CE2E4282A5.jpeg
    226 KB · Views: 81
Put 3 of one batch and 3 of the other batch in and see what comes out better in the end. With the exception of that one funky looking plug, both batches look ok.
 
These are RA bought plugs. The pic of the single plug is probably the worst of the lot, center electrode is the most crooked

Send those pics to Denso and tell them you bought them from Rock Auto and also include the return address they came from, Factory Motor Parts.
 
I contacted Denso USA. They say there's nothing that they can do to help me with determining authenticity. They said try buying from an authorized dealer, which RA is not, ( but where they shipped from is the same address as an auto parts supplier that is). They said Canadian Tire is an authorized dealer. I told him the general quality of these is low enough as to cast doubt, and I'd pay a few bucks more to have a better quality product and feel better about its authenticity.

I think I'll go with the RA bought plugs and keep the worst one in the most accessible location. I'll check them in 10 or 20k. If they're genuine, I'd hope they would look 98% the same. If there's wear, I'll know,
 
If anyone needs to buy at least 100 spark plugs, these guys offer a great deal. $0.75 per plug! Best Quality!

These "ASSEMBLED IN USA" plugs are made in Guongdong China, and can ship today!

 
This supplier is better at $0.68 per plug. Can produce 10,000 a day. These "DENSO JAPAN" plugs are made in Jhejiang China by Yiwu Kaixing E-Business Co. Ltd. Contact "Mr. Alex." BEST QUALITY!

 
These are the CT bought plugs. They generally look better, center electrode straighter (but not as good as I’d expect) and more obvious blue colour.

For me, that would go a long way toward convincing me to seek a different alternative next time.

And, to add additional information to the remark I made earlier about the stated 60-day warranty RA claims on NGK plugs, that is the same period as NAPA gives on NGK plugs. While it may suggest that RA is an AD, in lieu of an explicit statement like NAPA provides, it does not validate it as fact.
 
Had a similar problem with Denso Iridium plugs. Wore out after 30,000 miles. I also didn't notice any improvement the entire time I used them.

After that I switched to Autolite Double Platinum. Vehicle runs great. I think the Autolite Double Platinum plugs will last a lot longer.

I did some reading on just this subject and this is what I found.
Example, my 2016 Toyota Camry, 4cyl.......
Looked up on Rockauto
Denso Iridium TT, Denso iridium long life and Denso iridium power.
Both the TT and long life state "over 100K mile"
The power one does not give a mileage claim.
I had looked up the "power" version some time ago on the Denso website.....I had to look for it.....but found "30K" stated.
Toyota specs the OEM plugs at 120K mile life.

Personally, I am big on using ONLY the plug that is listed at OEM......in a Toyota, there should be a Denso and a NGK listed.
There are a couple Toyota vehicles that recently came with copper plugs....and one could "upgrade" to platinum / Iridium, but I would stick to as close to OEM specs as possible to avoid shorter plug life.

I did this look-up thing on the "power" plugs when I had my 2003 Toyota Sienna........where the upper intake manifold has to be removed in order to change the rear plugs. I CERTAINLY did not want to be doing that every 30K miles!!!!!

This is an example of what is marketed as a "upgrade" turning out to be a real downgrade!!!
 
OEM spec plugs are nickle plated standard NGK or DENSO (some engines left factor with 3 of each) and are spec'd to be replaced every 30k. I wanted the Iridium TT because they *should* last 100k-ish. For me it's convenience to not be changing them as often. I fully expect zero performance or economy gains in comparing new copper core/nickle plugs to the Iridium TT.
 
I bought DENSO Iridium TT plugs from RockAuto, part 4704, DENSO part IKH20TT. I am not overly impressed with the quality of them and have doubts about their authenticity. I emailed DENDO and they say RockAuto is not an authorized dealer. Seeing as RockAuto is a reseller, it is possible they have inadvertently resold me counterfeit parts.

There is a lot of info online about counterfeit DENSO plugs.

Things that appear authentic:
I have tried scratching the ink off the ceramic, it's baked on correctly
I have tried scratching the metal, it seems to be a quality alloy and not cheaply plated
The electrical tip appears genuine according to the various DENSO spot a fake guides
The box appears authentic, good quality printing, bar code seems ligit etc

Things that appear fake:
They have "ASSEMBLED IN US WITH FOREIGN CONTENT" stamped on them rather than "DENSO +++++++" not great quality stamping
The center ground electrode on some appears to be on a slight angle
The printing on the ceramic is slightly blurry in places and not as crisply printed as I'd expect.

Perhaps DENSO has a USA factory, and perhaps it produces a lower quality appearing product than the Japanese factory. As long as it works as well, I don't care. Given all the hype about the precision of the gap and special metals used to improve performance and longevity, the angled electrodes seem to be sloppy manufacturing and negate some of the alleged benefits of the precise tips used.

Compared to Bosch plugs I've bought in the past, these appear very cheap. I was under the impression DENSO was a high quality product and if these are genuine, I'm surprised DENSO would lower their standards.
Those look awful.
I have never seen such a crooked center electrode.
Those must be fakes.
The denso printing is also aweful.
 
Back
Top