Iridium worth it over Ruthenium?

[tbm5690]

I will be replacing the plugs in my MDX shortly. It's at about 104k miles on the factory Iridium plugs. Interestingly, NGK does not spec a ruthenium plug for me and instead only gives the laser iridium part number despite the 2016+ Pilot with the same J35 engine having a ruthenium option. My only guess as to the reason for the discrepancy is that on premium and a more aggressive timing profile the MDX has slightly higher performance, and therefore they want the better conductivity of iridium? I'm sure I'd have zero issues using the ruthenium part number allowed for the Pilot, and it looks to be just over half the price of the iridiums. All that said, I can get a set of 6 iridium plugs shipped from RA for under $100, so not a deal breaker. Thoughts?

 

[kschachn]

Only if longevity is your goal. Conductivity of the tip material is utterly irrelevant in a spark plug. The internal resistor swamps any minuscule difference in the tips.

All iridium gets you is a somewhat increased change interval. The only reason they switched to ruthenium was the high cost of iridium. That’s it.

 

[GaryMX5]

NGK Iridium IX is a cheaper option (vs Laser) and has an application for the MDX. I used these on one of my older Mazda's without issue.

 

[97prizm]

I will be replacing the plugs in my MDX shortly. It's at about 104k miles on the factory Iridium plugs. Interestingly, NGK does not spec a ruthenium plug for me and instead only gives the laser iridium part number despite the 2016+ Pilot with the same J35 engine having a ruthenium option. My only guess as to the reason for the discrepancy is that on premium and a more aggressive timing profile the MDX has slightly higher performance, and therefore they want the better conductivity of iridium? I'm sure I'd have zero issues using the ruthenium part number allowed for the Pilot, and it looks to be just over half the price of the iridiums. All that said, I can get a set of 6 iridium plugs shipped from RA for under $100, so not a deal breaker. Thoughts?

I'd look around and see if anyone else has swapped without any issues. Iridium plugs kept coming up for my 97 cavalier. I doubt it had even platinum plugs when new. It ran ok but the Iridium plugs had a different gap than what the manual specified. I found a set of platinum plugs and it seemed to run a little better.

 

[tbm5690]

Thanks for the replies. So any thoughts as to why NGK doesn't provide the Ruthenium plugs part number as a fitment option? I just noticed that they do for the RLX, RDX, and TLX but not the MDX. I'm guessing maybe just a catalog fluke?

 

[Jango]

I use rutheniums in my CRV and no reduction in performance or mileage.

 

[pbm]

NGK Iridium IX is a cheaper option (vs Laser) and has an application for the MDX. I used these on one of my older Mazda's without issue.

If I'm not mistaken The NGK Iridium IX is not rated for the high mileage use that Laser Iridium is.....it's more like a 60 to 70K spark plug.
In a V6 like the MDX I'd want the longest lasting plug available due to the difficulty accessing the rear plugs.

I also believe that NGK Ruthenium plugs are rated for longer use than NGK Laser Iridium plugs. In the application for both of my Fords on Rockauto the NGK Iridium IX gets 3 stars for 'Lifespan/ Durability' while the Laser Iridium gets 6 stars and the Ruthenium gets 7 stars. Whether these ratings matter in real life applications I have no idea but somebody at NGK feels that Ruthenium outlasts Laser Iridium.

 

[Snagglefoot]

If I'm not mistaken The NGK Iridium IX is not rated for the high mileage use that Laser Iridium is.....it's more like a 60 to 70K spark plug.
In a V6 like the MDX I'd want the longest lasting plug available due to the difficulty accessing the rear plugs.

I also believe that NGK Ruthenium plugs are rated for longer use than NGK Laser Iridium plugs. In the application for both of my Fords on Rockauto the NGK Iridium IX gets 3 stars for 'Lifespan/ Durability' while the Laser Iridium gets 6 stars and the Ruthenium gets 7 stars. Whether these ratings matter in real life applications I have no idea but somebody at NGK feels that Ruthenium outlasts Laser Iridium.

Yes, I think that was always the understanding of the Iridium vs Ruthenium comparison. For me I am about to change out my Iridium plugs on my 2008 Suburban with 285,000 miles. Very few people will own a vehicle long enough to be going onto their third set of Iridiums.

 

[spk2000]

I went with the Ruthenium plugs in my 04 Grand Marquis so they would last the life of the vehicle. Already had about 140,000 miles at that time now around 180,000. At first it felt like it idled smoother but that lasted about 10,000 miles and was back to a slightly rough idle. Car accelerates great snd runs smooth. No issues with them even though it not a Honda just sharing my experience. No problems or complaints. Many people belive Motorcraft is best in these 4.6 engines but I have 3 Grand Marquis and have not noticed a plug issue. My old 96 I bought with 82,000 miles came with E3 plugs but I was surprised how smooth it idled with them. Changed to the Motorcraft no noticeable difference.

 

[SOUNDMAN5000]

I will be replacing the plugs in my MDX shortly. It's at about 104k miles on the factory Iridium plugs. Interestingly, NGK does not spec a ruthenium plug for me and instead only gives the laser iridium part number despite the 2016+ Pilot with the same J35 engine having a ruthenium option. My only guess as to the reason for the discrepancy is that on premium and a more aggressive timing profile the MDX has slightly higher performance, and therefore they want the better conductivity of iridium? I'm sure I'd have zero issues using the ruthenium part number allowed for the Pilot, and it looks to be just over half the price of the iridiums. All that said, I can get a set of 6 iridium plugs shipped from RA for under $100, so not a deal breaker. Thoughts?

I'm no spark plug expert but I would not assume a plug is compatible even with both using the same J35 engine. I would assume as default ( before researching ) a more aggressive tune or a difference in perhaps compression, timing advance or boost pressure, etc may very well call for a different heat range in the plugs and that may be the reason a plug is not listed for your vehicle.

In general ( not always but most of the time ) I play it safe with OEM plugs, especially if I had 104K on a factory plug and it was still running well, thats thats the exact plug I would put back in it.

You hear so much about plug material but not so much about a plugs proper heat range in a plug.

 

[martinq]

I went with the Ruthenium plugs in my 04 Grand Marquis so they would last the life of the vehicle. Already had about 140,000 miles at that time now around 180,000. At first it felt like it idled smoother but that lasted about 10,000 miles and was back to a slightly rough idle. Car accelerates great snd runs smooth. No issues with them even though it not a Honda just sharing my experience. No problems or complaints. Many people belive Motorcraft is best in these 4.6 engines but I have 3 Grand Marquis and have not noticed a plug issue. My old 96 I bought with 82,000 miles came with E3 plugs but I was surprised how smooth it idled with them. Changed to the Motorcraft no noticeable difference.

Not on topic, but have you tried adding a Fuel System Cleaner or checking compression for cylinder variance?

 

[martinq]

I'm no spark plug expert but I would not assume a plug is compatible even with both using the same J35 engine. I would assume as default ( before researching ) a more aggressive tune or a difference in perhaps compression, timing advance or boost pressure, etc may very well call for a different heat range in the plugs and that may be the reason a plug is not listed for your vehicle.

In general ( not always but most of the time ) I play it safe with OEM plugs, especially if I had 104K on a factory plug and it was still running well, thats thats the exact plug I would put back in it.

You hear so much about plug material but not so much about a plugs proper heat range in a plug.

Most applications will have an NGK plug (or several) which are usually readily available. No need to worry about using a quality aftermarket part especially if it's from a mfg with the track record of NGK.

 

[martinq]

I will be replacing the plugs in my MDX shortly. It's at about 104k miles on the factory Iridium plugs. Interestingly, NGK does not spec a ruthenium plug for me and instead only gives the laser iridium part number despite the 2016+ Pilot with the same J35 engine having a ruthenium option. My only guess as to the reason for the discrepancy is that on premium and a more aggressive timing profile the MDX has slightly higher performance, and therefore they want the better conductivity of iridium? I'm sure I'd have zero issues using the ruthenium part number allowed for the Pilot, and it looks to be just over half the price of the iridiums. All that said, I can get a set of 6 iridium plugs shipped from RA for under $100, so not a deal breaker. Thoughts?

I'd be happy to go with the cheaper ruthenium option from NGK, conductivity is not an issue. I would also hang on to the old plugs as there's probably plenty of life left on them. Sometimes having a functional, old spare on hand is invaluable in an emergency.

 

[kschachn]

Most applications will have an NGK plug (or several) which are usually readily available. No need to worry about using a quality aftermarket part especially if it's from a mfg with the track record of NGK.

Yes it really doesn’t make a bit of difference except for longevity.

 

[Bwalker]

Iridium plugs are only advantageous if they are of the double Iridium style. Double meaning the center electrode is Iridium and the ground strap is also tipped with Iridium. Ruthenium are actually a better plug.

 

[Auto tech]

When it comes to spark plugs use what the oem originally used

 

[tbm5690]

Well, I guess I'll go with the Pilot's ruthenium part number. Cheaper than the laser iridium, and there is almost no chance that I will ever change them again as I only put on about 6k miles per year and will likely sell this vehicle within the next 5 years.

 

[GMBoy]

Just had a Lexus IS F sport in the shop for a tune-up. The NGK Iridium replacements were almost $35 each. They were a "high ignitability plug". NGK also listed a ruthenium "high ignitability plug" as well for about $12 a plug. Went with them as, to me, the ruthenium is an upgrade over iridium. Car runs fine, customer happy to save over $85 and prob never need another tune up in her time with the car.

 

[Snagglefoot]

Iridium plugs are only advantageous if they are of the double Iridium style. Double meaning the center electrode is Iridium and the ground strap is also tipped with Iridium. Ruthenium are actually a better plug.

I haven’t seen the term “ Double Iridium “ used, at least at Rock Auto. They do use the term “ Double Platinum” I have been using AC Delco and for the last 18 years they are what you would call “Double Iridiums. Here are pics from three different plugs the first two shots were in a 6.0 Chevy for an amazing 180,000 miles.

The next two shots are for an AC Delco 110 that went into the engine in 2018. It is also a “ Double Iridium.

They are going to be pulled this summer at about 290,000 mile and this new set of 165’s is doing in. This is Chevy’s newest design for Gen IV engines. Notice the “collar” at the base of the electrode. It too would be considered a “ Double Iridium.

 

[dfarr67]

There was a time not long ago when plugs were changed at 5k, and now you're complaining at 100k....