NGK Ruthenium Spark Plugs

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186
Location
FL
Thread starter
My IS350 was on the original, Denso spark plugs for 100k miles. Original owner couldn't be bothered to replace them at the recommended 60k interval. I replaced them with NGK Ruthenium plugs and immediately got a 2 MPG bump in gas mileage as well as a silk smooth idle. The idle was a little rough previously. Now, I've got about 25k miles on the NGKs and I've been noticing the idle getting rougher and rougher. Average gas mileage is still better than with the 100k old Denso's. I just looked online and I realized that these NGK Ruthenium plugs don't have a mileage associated with them. It just says they are supposed to last even longer than iridiums. Anyone else have any experience with NGK Ruthenium plugs, and how long they last?
 
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1,179
Location
Brittany / Canada
I may have 5000 miles on mine so can't really speak for longevity. Didn't notice anything special vs the previous iridium NGK on how engine ran or gas mileage - only time will tell. Curious on other's experience too.
 
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945
Location
Athens, GA
Unless that car is running a waste spark system, there's no reason those plugs can't go 60-100k. I doubt Toyota is engineering the ignition system to be hard on plugs. It is possible you have a weak coil or two that as the plugs wear it has a little harder time jumping the gap, but it's hard to say.
 
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6,688
Location
California
Toyota's D4-S engines also use a tri-electrode spark plug - the 2 side electrodes are there to allow a spark to still happen if the main one is carbon fouled. Does the new NGK ruthenium plug have that?
 
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945
Location
Athens, GA
Just out of curiosity I got to bouncing around the internet. Seems there is no real consensus on that motor. Some people say, if it came with the dual electrodes you need to use those or you'll get a rough idle. Others say they use 'normal' single electrode plugs just fine and that over the years Toyota dropped the requirement. Who knows, I'd say run them till it really bothers you and then change them, maybe back to the dual-electrode design.
 
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186
Location
FL
Thread starter
Originally Posted by nthach
Toyota's D4-S engines also use a tri-electrode spark plug - the 2 side electrodes are there to allow a spark to still happen if the main one is carbon fouled. Does the new NGK ruthenium plug have that?
No, the NGK plugs aren't tri-electrode. I noticed that difference when I pulled out the original Denso's.
 
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608
Location
The ATL
You're not going to see a mileage improvement with Ruthenium over Iridium plugs. They do last longer than Iridium or Platinum.
 
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1,206
Location
Lexington, NC
Just changed OE plugs on my Honda Accord 2.4L at 125,000 miles.....all 4 were evenly tan, still held 43-44 gap. I think they would have lasted another 100,000 mi! LOL BTW, it is wifes car and regularly gets 33-34 mpg. She seldom exceeds 65mph.
 
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15,146
Location
N.H, U.S.A.
Something wrong with that engine if it needs that plug. - and it's not an Aircraft. More electrode = more change of flame kernal snuff, and then pre- ignition when the buggers get yellow hot. Looks like an old Audi Bosch plug
 
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Messages
16
Location
VA
Originally Posted by tc1446
Just changed OE plugs on my Honda Accord 2.4L at 125,000 miles.....all 4 were evenly tan, still held 43-44 gap. I think they would have lasted another 100,000 mi! LOL BTW, it is wifes car and regularly gets 33-34 mpg. She seldom exceeds 65mph.
I hear you. Just replaced the original NGK Iridium on my '08 TL @ ~130k miles and they're a little brown but definitely didn't NEED to be replaced. The car is new to me, which is why they hadn't been switched out before. I'm using one of the ones I pulled out on my push mower and it's never run smoother. A lot of these Iridium plugs really can last the life of the vehicle; it's a huge difference from the old copper days.
 
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Messages
2,193
Location
SD
Originally Posted by circuitsmith
Where did you get the plugs? There are counterfeits out there!
I'm wondering the same thing.
 
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7,545
Location
MI
Originally Posted by zrxkawboy
Originally Posted by circuitsmith
Where did you get the plugs? There are counterfeits out there!
I'm wondering the same thing.
Anything is possible. When I talked to people at NGK this spring, they said that they knew of no counterfeits of the Rutheniums yet. She said the counterfeiters were concentrating on the most popular styles and that they had not yet caught up to the relatively new Rutheniums. Just my 2 cents.
 
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65
Location
USA
I know a person who purchased spark plugs from an AutoZone. The spark plugs were returned by a previous customer but were "new." The previous customer actually painted some old spark plugs from a different vehicle silver and stuck them in the box. This person who purchased the "new" spark plugs ended up destroying their engine. The plugs were too long.
 
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921
Location
D/FW Metroplex
Originally Posted by Dave_Mark
I know a person who purchased spark plugs from an AutoZone. The spark plugs were returned by a previous customer but were "new." The previous customer actually painted some old spark plugs from a different vehicle silver and stuck them in the box. This person who purchased the "new" spark plugs ended up destroying their engine. The plugs were too long.
Why did the person use the silver-painted plugs in his engine instead of returning them for actual new plugs?
 
Messages
65
Location
USA
Originally Posted by The_Nuke
Originally Posted by Dave_Mark
I know a person who purchased spark plugs from an AutoZone. The spark plugs were returned by a previous customer but were "new." The previous customer actually painted some old spark plugs from a different vehicle silver and stuck them in the box. This person who purchased the "new" spark plugs ended up destroying their engine. The plugs were too long.
Why did the person use the silver-painted plugs in his engine instead of returning them for actual new plugs?
They were painted pretty well and all the plugs purchased were painted, so none of them really stuck out. What can you say: weekend mechanic slaps something into his car without much thought. A "real" mechanic might have noticed the slightly dull silver finish instead of shiny nickel plating.
 
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