What happened to the 100,000 mile spark plugs?

[sk_pete]

Actually, I think the they have been 14:1 for the past couple of model years.

Miller cycle. The real ratio is less

 

[Oliveoil2]

12 Honda Fit, 120k plugs and they looked like they could have gone another round. Valves all in spec.

 

[Anthony]

This OEM AC Delco came out of my girlfriends 07 Tahoe 5.3. I think I changed them at 195,000. Surprisingly it ran fine!

I

 

[mightymousetech]

My 2004 X3 and my 2009 Clubman use a 100k mile plug change interval. The Condition Based Service in the 2 Series signaled a need for new plugs at 56k, and it does have a TGDI motor.

BMW spark plug interval is based on oil changes. Will show due every 4th or 5th oil change, regardless of mileage.

 

[dogememe]

Turbo stuff is harder on plugs. Don't see why DI would matter.

 

[CKN]

They push for lower cost of ownership... until you own the vehicle and they realize the service profits to be made.

First hand experience over on the trucks (Silverado-5.3) boards-guys are pulling out plugs at 100,000 miles and they look they could go several more thousand miles. So not sure about the second part of your comment.

 

[measureman]

My 2018 DI non turbo Elantra GT calls for spark plug replacement at 97500 miles.
And fuel additive every 7500 miles or 12 months.

 

[miden851]

Honda K24W engines call for 100k miles spark plugs replacement

 

[CKN]

My 2018 DI non turbo Elantra GT calls for spark plug replacement at 97500 miles.
And fuel additive every 7500 miles or 12 months.

This is factory OCI-and yes a bottle of fuel additive is recommended.

 

[TCL]

My manual calls for 40k turbo replacement and 75k non turbo 2018 model year

My 2017 Mazda 3 Grand Touring with 2.5 is 75,000 also.

 

[Luftmasse]

Newer Toyota GR series V/6 engines specify spark plug replacement intervals at 30k miles (copper) to 60k miles (iridium). The change occurred right around the time that D-4S (with DI) was added, but I can't say that this is what caused the change. At the same time, the spark plug specifications and part numbers also changed to "High Ignitability" spark plugs, the FK spark plugs have a 0.55mm electrode and the IK spark plugs have a 0.4mm electrode (both iridium). Most Toyota/Lexus models with the 120k mile interval use the much longer life SK iridium plugs with a 0.7mm electrode.
FYI, Toyota could potentially deny a emission system warranty claim if the plugs have not been changed or the incorrect part number was used.

Yes, the current 3.5L engines spark plug replacement interval is at 60k miles for some reason.

 

[Hillbilly Deluxe]

Direct injection happened.

 

[K20FA5]

Our Volvo calls for every 60,000 miles. I pulled these out tonight at 65,000. The gap was a little more than the new plugs, and it does run a little smoother too. BTW-It’s a shadow on the insulator, they actually didn’t look too bad.

 

[Ws6]

Both my 2020 VW Jetta 1.4 and my 2021 Mazda 3 Skyactive 2.5 (non turbo) both call for 40,000 spark plug changes. I'll assume the factory plugs are iridium. Even my old 1999 F-150 used double platinum plugs that I believe were 100,000 mile plugs.

Not that I mind doing the maintenance, but what's with the lowered interval?

My Rav4 Prime has 120K spark plug intervals.

 

[Whimsey]

Our 2017 Explorer with the 2.3 EB specs 100,000 mile spark plug intervals. I changed them at 60,000 miles because I didn't want them to seize in the aluminum head, we keep our vehicles well over 100,000 miles. The factory puts the plugs in dry. They were "squeaky" and tight during removal. The gap was well within factory specs. I could have just cleaned them and used anti-seize on the threads and re-used them but I got new Motorcraft replacements plugs for ~$4.50/ea from RA. I used anti-seize on the threads. I will leave these in for longer than 60,000 miles this time. Being a 4 cylinder these were easy to change.

 

[paulr1]

I had a 2019 BMW R1250GS. Came from factory with NGK Iridium plugs.

Discovered this at 27,000 kms and likely like this since 13,000 kms. Took the dealer till 40,000 kms to find out the bike had a faulty O2 sensor, even though i started complaining about serious detonation (and at times i think pre-ignition) at 13,000 kms and thru till 40,000 kms where i insisted thhey do every check possible to get to the root cause of the detonation. Slack, not interested workshop manager not taking ownership of the issue at 13,000 kms and finding the problem.

Plug from the other cylinder at 27,000 kms. Copper core under the Iridium tip burning away. Plug running hot.

Plug from 2020 BMW 1250GSA at 19,700 kms. Plugs still running hot and burning away under the Iridium tip.

BMW 1200 engines pre 2019 ran copper core plugs with replacement interval at 20,000 kms. At 20,000 kms the plugs came out looking like they could do another 40,000 kms.

With the 1250 engine, BMW replaced the copper core plugs with Iridium but retained the 20,000 kms replacement interval. It's likely no Iridium tips would have been attached by 30,000 kms on both the 2019 & 2020 bike.
Appears the plugs (same 8 heat range) in both the 2019 & 2020 engines are too hot and burning away.

Now running 9 heat range but will take 10,000 kms to see if this is the fix.

So much for the claimed longevity of Iridium plugs when run in BMW bike engines.

 

[cbear]

Spark plugs, especially in the Mazda SkyActiv engines fire more than once per combustion cycle. Also, these are high compression engines at 13:1. These are just a couple of variables to consider.

Sounds like an old Crane Cams ignition system I use to run.

 

[DemoFly]

4 pages of comments and I don't think anyone has got the right answer yet.

The direction injection demonizing is funny. It has no effect on spark plugs.

The answer is US passenger vehicle emissions standards.

 

[kebabaluba]

I`m gonna chip in with the theory that modern engines with high fuel injector pressure and high compression ratio just put a lot of strain on components. Modern engines develop same power as bigger engines did back in the day, that power comes at a cost and that is durability.