Are Ruthenium plugs worth the cost?
Ruthenium plugs
- Thread starter otis24
- Start date
It depends on what you’re seeking from the plug. The difference is small, but worth it to me.
I’m using a set in a high boost twin-turbo Audi 2.7T application and they are performing well, fewer misfires compared to copper equivalents when logging data, with a small increase in fuel mileage, and smoother (subjective, I know) running and accelerating.
The small difference probably isn’t worth it for most, but I like them and think the value they offer is worth the expense.
Id say yes.
I pulled 8 out at 110K they all worked really well and the edges were still pretty sharp.
I noticed no change in mileage or performance with new ones.
These came out of a towing half ton that had the snot revved out of it for most of its life.
Not sure if they are supposed to be better or worse, but Im pretty impressed with what Ive seen and experienced.
I pulled 8 out at 110K they all worked really well and the edges were still pretty sharp.
I noticed no change in mileage or performance with new ones.
These came out of a towing half ton that had the snot revved out of it for most of its life.
Not sure if they are supposed to be better or worse, but Im pretty impressed with what Ive seen and experienced.
Ruthenium costs $400 an ounce while iridium is $4700 an ounce. Sometimes they are cheaper to buy.
I'm trying to see the advantage other than the raw material cost of the manufacturer. Ruthenium has a melting point of 4200f , iridium has a melting point of 4400f. Iridium is harder than ruthenium. So how is ruthenium the better ?
EDIT: looks like iridium and ruthenium are similar in hardness 6.5 Mohs.
EDIT: looks like iridium and ruthenium are similar in hardness 6.5 Mohs.
From manufacturing stand point if they can make plugs comparable in performance but cheaper to make then they have a winner. AFAIK, they market Ru plugs as high ignatability ones, there must be something there?
I contacted NGK c. 2018 when the Ruthenium plugs were new to the market.
The rep said that Iridium plugs were rated for 100K km (c. 62K miles), and Ruthenium for 120K km (c. 75K miles).
Of course this was only weeks after I'd replaced the plugs in the '09 Kia Sedona with Iridium plugs, which involved pulling the intake manifold.
The rep said that Iridium plugs were rated for 100K km (c. 62K miles), and Ruthenium for 120K km (c. 75K miles).
Of course this was only weeks after I'd replaced the plugs in the '09 Kia Sedona with Iridium plugs, which involved pulling the intake manifold.
JHZR2
Staff member
I got the NGK ruthenium plugs for less than the OE Honda or the correct NGK iridium plugs. There was a more generic NGK iridium for less, but I’m happy with the ruthenium ones…
They're worth it if the job is difficult 
Ruthenium costs a fraction of iridium and that's probably why ruthenium has entered the stage. I mentioned in another thread I was pulling spark plugs every 20k miles or so not only to inspect them but also to prevent the threads from seizing. There's no way I'd leave spark plugs in the head for more than maybe 40k miles without looking at them even if they are capable of going 120k miles. Longlife or lifetime service items often cause indirect neglect of maintenance.
Ruthenium and iridium are in the platinum group of metals. They are very similar with minor differences in melting point and hardness. What's next, osmium spark plugs?
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They're worth it if the job is difficult
That is why I went with them when I did plugs on my Outback.
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- Sep 2, 2016
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Are there any vehicle manufacturers using ruthenium spark plugs yet? You'd think they would be all over something cheaper with a longer lifespan
No, because you don't know the exact electrical properties of the plugs and whether they perform in a manner not stressful to the ignition coil system of your vehicle. They may last but wear out upstream parts so that you eventually, over a long period of time, throw a code for misfire. You would rather have spark plugs being devoured in a worn out system but still have functional coils.
They ran like garbage over the NGK LASER Iridium but I don't know why. They were marketed as the best of the best;even had the plugs indexed and they never got better. Bought a few boxes of the 9696 whatever and using on them from now til 600k.
I say it's a product to get people to buy new cars by killing old ones.
It managed to kill a couple old ignition coils on a Toyota matrix, which is saying a lot. That car had a frail fuel pump, so it ran lean, but on the stock iridiums, it just showed that the plugs were wearing out well before the stated 100k life. But the coils never faltered. I switched to Ruthenium last October. They felt okay to start...but recently, yeah, misfiring cylinder 3. Also interesting to note...there was "corona" burning on the plug with two old coils but not the plugs linked with the two new Denso coils I had installed, meaning its damage to the coils will not be immediately noticeable if its a newer vehicle.
That's compounded by an independent brake caliper issue(grease may not be for Toyotas, sorry 3M silicone, but you get a minus for that) and probably a failed brake hose. So it delayed me from dealing with the braking system because you have things vibrating and two things broken at the same time. And I was strapped for time and didn't go through things as thoroughly as I would have.
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I'm curious if Ruthenium plugs are really causing issues or if it's something else.
I.E. a Ruthenium plug, store bought with proper gap.
I've looked online and haven't really seen too much talking about issues with these.
I put 4 in a 03 Camry...maybe a year ago and seems fine or better. Scan tool showed no codes before or after.
This dialogue makes me curious if I should pull them.
VersatileGuy: Where on your plugs was there burning? Like on the boot or top?
You say, "it just showed that the plugs were wearing out well before the 100k life?" I'm curious can you clarify what showed?
Like did you pull and look at the plugs or did you analyze some live data changes at different millage intervals or something else I'm not familiar with?
Did you get rid of your misfire? Did you test one of the new coils on #3 to see if it went away and if the current #3 coil caused a misfire on wherever you moved it? Also, when you say they wear out upstream parts do you know this for a fact or an assumption? Like are they out of spec or something maybe?
Revving: What did you put those in? Store bought? Check gap prior?
I'm wondering if we could get some answers to all these questions by a quick call to NGK or the front desk at some of the auto parts stores to hear what they have been seeing from folks?
I.E. a Ruthenium plug, store bought with proper gap.
I've looked online and haven't really seen too much talking about issues with these.
I put 4 in a 03 Camry...maybe a year ago and seems fine or better. Scan tool showed no codes before or after.
This dialogue makes me curious if I should pull them.
VersatileGuy: Where on your plugs was there burning? Like on the boot or top?
You say, "it just showed that the plugs were wearing out well before the 100k life?" I'm curious can you clarify what showed?
Like did you pull and look at the plugs or did you analyze some live data changes at different millage intervals or something else I'm not familiar with?
Did you get rid of your misfire? Did you test one of the new coils on #3 to see if it went away and if the current #3 coil caused a misfire on wherever you moved it? Also, when you say they wear out upstream parts do you know this for a fact or an assumption? Like are they out of spec or something maybe?
Revving: What did you put those in? Store bought? Check gap prior?
I'm wondering if we could get some answers to all these questions by a quick call to NGK or the front desk at some of the auto parts stores to hear what they have been seeing from folks?
| iridium melting point 4,435°F Electrical Conductivity 2.1×10^7 S/m | ruthenium melting point 4,233°F Electrical Conductivity 1.4 x 10^7 S/m |
Iridium is more durable in high-performance applications. It conducts electricity better, is more heat resistant, and the electrodes can be made finer. Ruthenium plugs can last longer under less demanding conditions and they cost less.
I have a 4cyl engine.
From the passenger side, two plugs were installed with a brand new Denso ignition coil last October(I think these are cylinders 1 and 2). Two were left with the old originals; these were closest to the driver side. I kept two of the old ignition coils from 1 and 2. Cylinder three tossed a misfire a month or two ago, but it was misfiring before that. 4 I believe was questionable.
So, I put one of the original ignition coils from 1 or 2 into 3. 3's "hole grip" was totally gone. There was no feeling that it was tight enough to latch on to the stick part of the spark plug(cue the TWSS jokes). I just pulled it up with no resistance whatsoever. So that's the physical failure. Cleared the codes, installed coil. The code didn't return and the car ran better for the short few days it had coil 1 or 2. I eventually took out the Ruthe-plugs and put in an old set of IK16TTs and startup immediately because shorter with those plugs from 2019.
I installed a bastard junkyard coil(the screw holes don't line up) from a Yaris onto number 4 temporarily and whatever misfiring that remained was cured. That left me to finally isolate the probable failed brake hose that was causing me grief at the same time the engine tossed the misfire code. The engine doesn't run like it's lost all power, struggling mightily to even go up a hill.
The black burned insulator is above the socket metal area. 1 and 2 had very little discoloration(not none) at the ceramic bottom. 3 and 4 had considerably more. And the time elapsed was short, as they were installed last October or November.
This pic is of #3.
I've had ruthenium NGK in my Mazda pretty much since they became available to purchase on Rockauto, 2019 or so?
Approx 40000Km, nothing special to declare. I might go look what they look like for fun. I had replaced the coils with new Delphi coils around 50K Km ago.
Approx 40000Km, nothing special to declare. I might go look what they look like for fun. I had replaced the coils with new Delphi coils around 50K Km ago.
