Stick with factory NGK. Lots of posts about issues using non factory plugs. Depending on what year car you are good to 100k miles. Early models had 30k mile plugs but Ma MOPAR gave her blessing to swap to the later 100k mile plugs.

 

I have 16 new NGK Iridiums awaiting installation here. Had one set of copper core installed at the dealer a couple years ago, no way am I doing that again. I think it's up over $400 for them to change plugs, I can still manage that task even if it takes me all afternoon.

 

Its an easy task - takes a few extra minutes the first time but very manageable. I never inquired about cost at the dealer but the prices I have seen others post see very high for the job. I used Iridium IX - LZTR7AIX-13 - couldn't find them in stock at the auto stores so I bought them on ebay from a local seller.

 

Factory plugs.

 

Having come from the automotive repair clan as a occupation I've been taken back at what some dealerships charge for such simple repairs. For those of you out there that have swapped out plugs , is it a common practice to apply a very small amount of silver anti seize compound to the plug threads and silicone dielectric grease in the plug boots before reinstalling the coils?

 

If your new plug has shiny chrome like color threads, that is an anti seize coating so don't use any more. Not sure about the grease, might make installation and removal easier.

 

I'm still trying to figure out what is meant by lifetime, as in transmission fluid for example. In my Ford F150 manual, it states that transmission fluid is rated "lifetime". Does that mean when the transmission fails, it's now lifetime? Rear end fluid is the same...I guess when the rear end fails, it's also lifetime.

I'm old school in some ways. Still like replacing oils at a decent time interval. For me, that's every 30K for an automatic and rear end. And for Ford, plug changes are in the 100K range.

 

“Don’t worry about the <insert component name> fluid, it’s a lifetime fluid and doesn’t need changing!”

Translation: under normal driving conditions, the fluid is good enough to do its job (inside a sealed unit) for the length of the powertrain warranty that covers the components in question.

So in reality, you conceivably leave the transmission, etc. fluids alone and you’d be fine for as long as you own the car, or the first 60K-100K miles, whichever ends first.

If you want to keep the car past the end of the powertrain warranty period, that’s a different story. The fluids will have to be changed. Period. Full stop.

 

NGK

 

I'd like to know if anybody has tried the E3 plugs in their Hemi? I tried them in my Harley, and they made such a noticable difference that I put them in my JD mower, my Mustang GT, then my F150. A noticable gain in each one. Now I'm thinking about trying them in my 09 supercharged SRT. What do u guys think?
Jeff

 

There are 2 spark plugs in each cylinder, complete combustion of the air/fuel charge should not be an issue.

If a different kind of spark plug does not bring about a more complete combustion event, at best it would only perform as well as the kind being replaced.

Buying and installing 16 spark plugs only to receive the same performance in return isnt a wise use of one’s resources IMHO.

And then there is the possibility the new plugs will not perform as well those they replace.

 

I use NGK in everything. Never a problem and some engines showed performance improvement. My old yacht had 8.1 Mercury 420 HP twins in it. Came with AC Delco's, traded them for NGK's. Gained 400 RPM at WOT on one of the engines and 200 RPM on the other.

 

I mentioned in my intro that I come from a generation when carburetor adjustments , valve adjustments and, spark plug
replacement was a common practice. Not so in today's world. I was really surprised to learn that present day iridium
spark plugs can last tens of thousands of miles. No need to replace like in the old days. Many different things contribute to this extended life of the spark plugs in todays world. Should you elect to replace spark plugs what kind of spark plugs are factory type ? I've read NGK is a factory installed item. Long time Chrysler engineer Larry Shepard recommends using a Bosch brand plug. I'm not sure if spark plug replacement in todays world is as prevalent as it was "back in the day" So which flavor are you using?

Have not had to change the plugs in my 2020 Scat Pack yet. When the time comes I'll just go with the factory plugs. For a number of cars over the years when it came time for plugs I stuck with the factory recommended plugs. Upon replacing the old plugs at the recommended mileage the engine never ran better (or worse). That it never ran better -- at least as far as I could tell with my seat dyno -- was comforting for it told me the plugs were still performing up to spec.

Had I changed the plugs and the engine ran better I would have shortened the change interval. No sense running the engine with lousy plugs and loading up the engine with hard to remove deposits.

 

Builder/tuner recommended more frequent plug changes so I plan to do them every couple years regardless of how long they are supposed to last and I’m ahead on oil and brake fluid changes, but I will likely do coolant and diff services next year when it might have 19k miles. I didn’t notice anything change with new plugs which honestly, is a good thing. I don’t drive many miles but would prefer to know they are clean, plus I have been known to sell cars without much forethought or when the time seems right (something else grabs my attention) and it’s good to know everything is up to date. I have other cars with lifetime fluids - all are less than 10-12k miles and have either had the fluids changed or will soon - nothing lasts a lifetime in a car.

 

My book for my 17RT says 100k miles for plugs but any one really waiting that long or are you guys changing them before? I’m like 38k in and wondering if I should change them out…

 

You can change them out anytime you want, but there will not be any benefit to replacing the iridium plugs before 100K miles. They will be working as designed up to 100K (and even a little beyond), and so putting new plugs in before 100K will only give the engine what it already had - a set of working spark plugs.

 

I replaced mine at 90k ish miles and they looked good. Replaced with OEM which are good for 100k.

 

also - a little dab of dielectric grease inside the plug boot - it accomplishes a couple of things

• it keeps the boot from sticking to the plug insulator
• it will seal out from moisture getting inside the boot and potential corrosion of the terminal

(this in done on the assembly line)

 

I’ve decided I’m going to wait till 50k mark to go ahead and change them! - sorry to hijack the thread.