Spark plug replacement - how often & anti-seize?

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Today I changed the plugs in my 2003 Saturn LW-200, L61 Ecotec 2.2 engine. The plugs supposedly would be good for 100K miles, but I would be afraid they would not come out cleanly after 100K. And it is an easy task on this engine, and not so expensive (AC Delco iridium $ 7 each at Advance Auto Parts, & Delco has a $2 / plug rebate now) - so I follow an interval of approx. 50K miles. And with a shorter interval, I am following what the AC Delco site says abut their plugs - NO anti-seize.

Maybe when the job is really difficult, it makes sense to go the recommended range, and maybe then it would pay to use some anti-seize.

I will say that after 50K, the gap was still good - a tight .045.
 
I use a little anti seize and change at 100k miles. I don't go gorilla tightening them. Just a good snug. Use Denso in my Toyotas.
 
Originally Posted By: Leo99
I use a little anti seize and change at 100k miles. I don't go gorilla tightening them. Just a good snug. Use Denso in my Toyotas.


+ 1 same here

According to briansmobile1(youtuber), spark plugs manufacturers recomend not to use antiseze because it will mess up with torque values and they would be liable if you strip the treads on your aluminum heads,
 
I had a 2000 Intrepid with the awful 2.7. Sold it at 132,000 with the factory plugs, I took them out twice and they looked fine. Checked gap and back in with a little anti-seize,
 
I use OEM plugs at OEM intervals and OEM service instructions.

Has always worked for me, and the plugs coming out just look like dirty versions of the ones going in.
 
It really depends on the type of plugs used. Iridium will last the longest (100,000 miles or more, typically), followed by Double-platinum (60-80k miles), then Platinum (~40-60k miles), then Copper (~25-30k miles).. give or take.

Then again, it can also depend on your driving habits, climate, etc..

A few months back, I decided that it was time to replace the plugs in my 2010 Fusion.. The car had 215,000 miles on it at the time, and I just got the feeling it was time..

So I went and ordered a set of Autolite Double-Platinum plugs and did the change. What I found just blew my mind...

- The plugs that I took out were the original FACTORY plugs, which meant that they were still running after 215,000 miles of service!

They were FoMoCo(NGK) fine-wire Iridium plugs and the tips still looked amazingly good.

m7chhg.jpg


I went ahead and changed the plugs anyways, but realistically, they probably could have gone back in for at least another 25k miles, maybe even 50k. The trick is, I live in Phoenix, which sees very little rain, virtually no snow, maybe 1-3 days a year under 32F, and I do about 90% highway driving. All of these factors could potentially double or maybe even triple the lifespan of a spark plug in a well-maintained engine.

For most cars, however, I doubt you'd really be able to reliably go longer than about 100,000 miles, even on a set of Iridium plugs.



... Also, I always add just the SLIGHTEST amount of anti-seize compound on my plugs and spread it out super thin.. just to be safe. Just remember though, if you use anti-seize compound, you have to be extra careful tightening, as koffy points out.
 
My spark plug change interval varies by vehicle. In my 88 van I change them every 35K miles, my 08 Century I changed them IIRC at 85K miles, my Liberty 38K miles. My Rubicon says 100K, I doubt I'll wait that long. I've used anti-sieze for decades on plug threads and plan to continue doing so. I've read the discussions for and against, for continues to win out in my mind..........
 
Copper plugs I change every 30K miles. The iridiums I would change at 100K miles. And a tiny bit of anti seize is plenty
 
Many if not most AC Delco iridiums are NGK (reboxed Laser Iridium), and NGK says no antiseize ever.

And even if you went the full 100k or even 200k, you still would not need antiseize
smile.gif
 
I changed out the plugs on a Chevy HHR with the 2.2 Ecotec at nearing 90k and was getting some misfires. Were iridiums. I would take note of that engines timing chain tensioner was updated because the older system was wearing and would jump and there goes your valves. Found that out the hard way. Kit to replace the chain and tensioner system is around $100 and not that hard of project. Good litte engine otherwise IMO.
 
SirTanon - wow, after 215K. There are probably some reports out there of police cars or taxis or like that with insane miles on the original set of plugs. I will bet the gap was still about right with the ones in your picture.
 
I have a 2.2 ecotec in my Malibu. Changed out the original plugs last year with 160,000 miles on them. The gap was twice what specs called for but they worked fine. Put in new AC Delco plugs and did not use anti seize as the manual says the new plugs come with a coating on the threads that precludes the use of anti seize.
 
Originally Posted By: tomlct
SirTanon - wow, after 215K. There are probably some reports out there of police cars or taxis or like that with insane miles on the original set of plugs. I will bet the gap was still about right with the ones in your picture.


You got me wondering.. so I went and grabbed my gapping tool.

They're all pretty close, but there is a little measurable wear. The plugs come pre-gapped at 0.50.

Plug 1 - 0.51
Plug 2 - 0.53
Plug 3 - 0.54
Plug 4 - 0.52

Gotta say I'm pretty amazed.
 
If the plug has black color threads(i.e. non plated) then the use of ant-seize is recommended. If the threads are plated, then no anti-seize is required. According to NGK, a layer of the plating acts as the "anti-seize".
 
Originally Posted By: mclasser
100K+ on NGK double plat plugs. No antiseize needed with them.


IMO this is a falsehood from NGK and they and the manufacturers know it. The fact is if the vehicle is operated in certain climates like the rust/salt belt and depending on how exposed the plugs are to the outside air they will still seize tighter than as a bulls backside in a hurricane.
It seems it is more acceptable and easier for them to deal with an occasional stripped out thread they can blame on the installer than recommend a product that if misused can potentially cause a cat damaging misfires (problems with the EPA) and striped threads from over torquing.

Over the years I have dealt with dozens of stuck plugs even the NGK plated ones in engines used in the salt belt. Most manufacturers also recommend no anti seize for the same reasons but have no problem whatsoever issuing a TSB for its use when the broken and stripped plug claims mount up on some engines under warranty where the owner couldn't be blamed and the repair is on them.
 
Originally Posted By: SirTanon
Originally Posted By: tomlct
SirTanon - wow, after 215K. There are probably some reports out there of police cars or taxis or like that with insane miles on the original set of plugs. I will bet the gap was still about right with the ones in your picture.


You got me wondering.. so I went and grabbed my gapping tool.

They're all pretty close, but there is a little measurable wear. The plugs come pre-gapped at 0.50.

Plug 1 - 0.51
Plug 2 - 0.53
Plug 3 - 0.54
Plug 4 - 0.52

Gotta say I'm pretty amazed.


I have read many cases (for all car manufacturers) where spark plugs were pulled out of a motor at/near 100K (when this is the interval specified) and they looked satisfactory. No BITOG "over maintenance required" on spark plugs.
 
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