Spark plugs

wow, that's very unusual. i'd be concerned with your engine. any change in performance with the new ones?

 

These do not look like the factory recommended iridium plugs. Those will go over 100K.

 

Picture of other half of plugs? No iridium plug I've ever seen has had wear on the center electrode like that, even after 100k miles.

Were these the original plugs from when car was purchased or were these replaced 56k miles ago?

If they are replacements, where were they purchased? Potential Chinese model?

Seems to be a LOT of counterfeits now.

 

Maybe the new are counterfeit too? Isn't there supposed to be a little cylindrical protusion on the ground electrode? I've attempted to sketch:



I've had ours out for a look, but can't remember.

 

Here's some photos of some SK16R11s (#3324) I recently removed. They had around 80k miles. Also a link to the denso website. The sk16r11s have a very small/thin platinum disk on the ground electrode. It's semi-visible in the photos. The Denso #4701 has a much more visible platinum piece on the ground.

https://www.densoproducts.com/product.aspx?zpid=11132

 

One thing: isn't the revised Denso number SC16HR11, a slightly hotter plug? Not sure of the story, but I think Toyota and Denso huddled and decided to go to a hotter plug, due to build-up? FWIW I've had a look at ours (SC20HR11) and they look fine.

 

Maybe the dealership got hit with some fakes. I heard a few decades ago about a Sony warehouse in the UK that found they had fake tapes in stock: I think someone had bought genuine and then returned what were in fact fakes.

 

There was another thread recently about SC20 plugs. Same type of box and markings, purchased from ebay as a pack of 4 individually boxed plugs I believe. The plastic bag they arrived in said made in China.

The plugs I have I the photos in post 8 are stamped around the circumference (under the hex) "Assembled in USA with Japanese and US parts" or something very similar. They have no DENSO stamped in that area, but mine are SK16s and the others are SC20s, so they may be a bit different.

Counterfeit spark plug ID help request | PriusChat

The Chinese version, for those that want a plug that looks and feels like a DENSO, but is rated at 70,000 kilometers (44k miles)

Iridium spark plug , Toyota Spark Plugs DENSO SC20HR11 OE 90919-01253 For Toyota length 26.5 mm

As opposed to the SC20HR11 at the DENSO website, which is rated for 80-100k miles.

https://www.densoproducts.com/product.aspx?zpid=11168

 

I would say go to one of the autoparts stores and ask to see what theirs look like.

 

the plot thickens...

 

counterfeit parts from a toyota dealer, what's next?

 

Installed some Denso Plugs SK16R11 into the 2005 I purchased last week. Photo for reference if anyone is curious about the small disk bonded on the ground electrode.

 

Counterfeit plugs missing this?

 

I'm not sure, tbh, but it's one more thing to verify before installing new plugs in your car. I do know for fact, that if that disc is missing, the ground electrode will wear fast. I check all new plugs now. I bought a black 2005 in August 2018 and started getting misfires a few months later while my son was driving home from work. It was bad enough it was causing the CEL to flash. Found one plug with a ground electrode that had extreme wear and a ~2mm gap. I tossed that one in the trash. Either the disc fell off after install, or it was never there. The photos I posted earlier in this thread were the 3 other plugs from that car. They're still totally usable if needed. I keep some good "old" plugs handy as a "just in case" thing. I should have installed new plugs when I bought the car...lesson learned.

 

Congrats on inspecting ahead of maintenance book.
IMO job well done, yes you needed new plugs.