How long will my spark plugs last?

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Two vehicles...

1) 2000 dodge caravan has platinum plugs changed at 63K and now has 123k on it.

2) 1995 Chev Lumina has standard (not platinum) spark plugs changed at 122k and now has 171k on them
 
They will last as long as they take to start misfiring
grin.gif
 
If youre not noticing any misfiring or poor economy theyre probably both ok. The non platinums are probably at the end of their life, if not past it. The platinums should be good for another 30-40k, but it can never hurt to swap them out.
 
The plugs in my 2003 Pontiac Montana are the originals from the factory. They have 117K miles on them. No problems with misfires yet. The owner's manual says to change them at 100K miles.

I tried to change the rear bank and gave up. Tried to follow the procedure in the FSM since I already had the wiper mechanism out to change the struts. I just could not get my arm back there.

I figure it will be easier with the intake removed, so I'll change the spark plugs when the LIM gaskets need replacing. Or if I ever need to lower the engine/trans/subframe for any reason.
 
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Originally Posted By: OVERK1LL
They will last as long as they take to start misfiring
grin.gif



Good, pragmatic advice. The manual for my 2012 Hyundai Veloster doesn't even specify or recommend a change interval. It just states "Under severe conditions, change more frequently."
 
I would have changed those long ago in both cars. General rule of thumb (based on my experience) is:

copper=30k max
dbl platinum=60k
Iridium=100k

for best performance respectively
 
I had one of my drivers asking me:"When do I need to change plugs?" at 178k on his Lincoln Town Car. They looked bad when we pulled them, but the car ran like new. The same driver asked about his belt at 209k. Boy, I never saw a belt like that. He is the owner, great customer service skills, but needs help with some maintenance items. I don't know what we are going to do when we run out of LTCs. They are not being made any more.

Double plats are good, regular plats may be a gimmick for DIS cars like ours. Iridiums are proven champions in longevity.
 
79K on factory Champion platinums in a Caravan,and they were shot.Huge gaps,missing ceramic,missing platinum pads....surely couldnt have gone 100K.
 
Originally Posted By: beast3300
I would have changed those long ago in both cars. General rule of thumb (based on my experience) is:

copper=30k max
dbl platinum=60k
Iridium=100k

for best performance respectively


Denso designed their iridium's to go 200k without a drop-off in performance. I have a Denso research report which shows the results. Don't know how to attach it here but let me know if you are interested and I'll send it to you.

Edit: Denso presented this paper at an SAE meeting - it is 1999-01-0796.
 
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Plugs are a pay me now or pay me later item. Increased gap can cause coil problems. Then you start chasing solutions and spending much more money then what is needed.

Both of those vehicles are super easy to change plugs on. If they were mine they would get double platinums and 50,000 mile changes.

Not to mention you have a much better chance of successfully removing them without issues.
 
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Originally Posted By: artbuc
Originally Posted By: beast3300
I would have changed those long ago in both cars. General rule of thumb (based on my experience) is:

copper=30k max
dbl platinum=60k
Iridium=100k

for best performance respectively


Denso designed their iridium's to go 200k without a drop-off in performance. I have a Denso research report which shows the results. Don't know how to attach it here but let me know if you are interested and I'll send it to you.

Edit: Denso presented this paper at an SAE meeting - it is 1999-01-0796.



Yes I would like that. I have pulled factory Denso's out of Toyotas from 100k to let us say 130k and the ground strap is usually worn into a wedge. The iridium part looks fine though. This is in COP ignition 4 cylinders. I am not doubting the Iridium part may last but the non-Irdium side or porcelin is another story.
 
The plugs in the Caravan may have some life left, but I'd probably change the ones in the Lumina.

My Ranger came from the factory with platinum plugs that were supposed to be good for 100K miles, but I used a lot of ethanol in the truck and I think that accelerated wear. The center electrodes were really worn at 80K miles and the gap was off on all of them. It was still running fine though.
 
Originally Posted By: OVERK1LL
They will last as long as they take to start misfiring
grin.gif



Actually very good advice. Any modern car will immediately throw a code and illuminate the CEL the second a misfire occurs.

I had the OEM NGK Plat/Irid Hybrids out of my engine at 60k miles and they looked almost new. Recommended interval on my car is 105k miles or so.
 
Originally Posted By: beast3300
Yes I would like that. I have pulled factory Denso's out of Toyotas from 100k to let us say 130k and the ground strap is usually worn into a wedge. The iridium part looks fine though. This is in COP ignition 4 cylinders. I am not doubting the Iridium part may last but the non-Irdium side or porcelin is another story.


Google the SAE number and you will find it easily.
 
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