How To Clean Ngk Iridium Spark Plugs

At about 100,000 miles I was thinking of replacing plugs in my 2014 5.7 Hemi, so I removed both from cylinder #2 (because it was easiest to reach) for inspection. They still looked brand-new, so I put them back in and stopped worrying about plugs.

At 223,000 miles, I'm getting a recurring "cylinder 2 misfire" code, and I naturally thought "maybe it's the plugs". So I ordered plugs from Rockauto and the Geartech swivel socket from Amazon, and prepared myself to get dirty.

So far I've completed the left bank (cylinders 2, 4, 6, and 8). To my surprise, the plugs look little different at 223,000 than they did at 100,000. Even the gaps appear not to be eroding. That's a 1/16" (0.0625") drill bit in the photo for comparison.

Another thing I noted was that the rubber spark-plug boots seal very well to the heads. There was no sign of dirt or water infiltration into the bores, and all plugs came out easily. I unscrewed all using fingertips on the extension once they were broken loose.

If I hadn't already bought plugs, I'd probably clean these and put them back in. And now I'm sorta wishing I'd gotten Iridium again instead of Platinum, but both were recommended for my application and the Platinums had a rebate that made them about $2 apiece

My question is, do others see this plug longevity for NGK Iridium ILZFR5E?

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Last edited: Oct 21, 2021

Treburkulosis

I am running those plugs in mine. I like them. As for the boots, they are life time meaning you should never have to change them. Id do a PCV as well.

Treburkulosis

I found Summit of all places to be the cheapest.

I feel you. My FIL has a topside creeper that I used when I did mine. It was a blessing, but I had a sore abdomen from laying my fat a$$ on it.

Do you have the Gearwrench 80546 magnetic swivel spark plug extension? Worth every penny.

Yes, I ordered it from Amazon before starting this job.

BTW, there's a damn good reason why NONE of the YouTube videos show anyone using a torque wrench on cylinders 5 and 7!

Luckily the plugs are new, so you can feel when the washer contacts the head, feel the period of near-constant resistance as it crushes, then give it "just a little more" when the tightness suddenly increases.

Last edited: Oct 21, 2021

With that many miles, I am amazed that you could get them out of the head. That would be my worry.