What happened to the 100,000 mile spark plugs?

[sohccammer427]

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?

 

[Hall]

I'll assume the factory plugs are iridium.

That may be a mistake. It's odd that both VW and Mazda say 40k miles though as automakers are always pushing for "lower cost of ownership" and would favor Iridium plugs for longer life.

 

[Quattro Pete]

What happened to the 100,000 mile spark plugs?

Direct injection happend.

 

[2strokeNorthstar]

Direct injection happend.

Our Turbo Direct Injection Nissan had the plugs changed at 90k miles and looked great.

 

[texdogs]

I just replaced spark plugs on my 2.5L turbo Mazda 6 at 40k. Plugs were easy to replace and now available at auto parts stores NGK is the oem save money at advance auto with coupons. I’ll try to post pictures later on of old ones.

 

[texdogs]

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

 

[PimTac]

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.

 

[ripcord]

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

 

[sohccammer427]

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.

Interesting. I had read about the 13:1 compression, which is indeed high for a gasoline engine, but did not know about the multiple fires. Does it fire multiple times on a power stroke for complete combustion?

 

[jeepman3071]

That may be a mistake. It's odd that both VW and Mazda say 40k miles though as automakers are always pushing for "lower cost of ownership" and would favor Iridium plugs for longer life.

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

 

[Mulligan]

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

I just checked the scheduled maintenance for 2021 models on Mazda's website. It's still 40k for turbo and 75k non turbo.

 

[RooflessVW]

VW spark plugs interval has been 40k for as long as I can remember.

 

[skyactiv]

My Elantra says 40K because it is one of the 12 made with a direct injected turbo engine.

 

[UncleDave]

higher compression and multiple and or extended spark events per cycle takes a toll from what I can discern.

 

[Wolf359]

Mercedes has had multi spark ignition systems for a while. I believe at first it was up to 4 times per cycle and now the latest is up to 5 times per cycle. And they have you changing them at 60k. Years ago, they used to have two spark plugs per cylinder so that those V12s had 24 spark plugs.

I think Ford has a waste fire system ages ago so that was two per cycle but even then, those plugs were good for 100k although at 100k you could see they were worn.

 

[gathermewool]

Why would high compression, in and of itself, affect the life of a spark plug?

 

[Nick1994]

100k mile plugs in my direct injection Genesis

 

[MCompact]

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.

 

[OilUzer]

Learned something new!
Didn't know about multiple or extended spark events or ignition ... I thought it's fired once per cycle.

How does it work? Need to Google I guess.

 

[zzyzzx]

Direct injection happend.

I thought that it was the turbo chargers that did this???