Don't be like me. Change your spark plugs on time.

I set my plugs at the bottom of spec, and replace them at the top of spec. That has consistently been 30,000 miles.

 

50K with copper from a Toyota tech. Don't waste your time at 30k.

 

2015 4Runner @ 92k miles

 

Modern coil-on-plug systems can just hammer a spark through plugs that would have had my old distributor V8 sputtering and coughing all over the place.

 

One thing that should be mentioned; one of the possible downsides to leaving the plugs in past their due date is when the coil has to hammer the spark to through an old plug it can expose weaknesses and create them in the stick coil. An old high mileage past due plug typically has an increased gap along with somewhat poorer electrical characteristics compared to new. To fire through/across that requires more voltage esp as the gap increases, that in turn causes the coil to work harder which ramps up the heat inside the coil. One of the more common failures is one of the coils will start firing out through it's side to metal nearby which can't be seen with stick coils but the ecu will pick up the misfire. Remember, the insulation on the stick coils ages also. Once that type of misfire starts that stick coil is toast, it's new electrical path out the side quickly becomes easier for it than original path down through the sparkplug. To sum it up; old plugs can cause the ignition to work harder and if you're like many of us, your ignition is older than the sparkplugs that needed replaced. Running a sparkplug way past it's recommended life may not save anything and could cost you. For an example, look at GT2000s post above.


"As spark plugs wear down, the gap in each spark plug is fired is widened meaning the coil needs to provide a higher voltage in order to bridge the gap. This additional strain on the ignition coil may cause voltage overload leading to overheating and eventually failure." Link

 

Well put. Your 100% right about everything you said. I replaced my coils after that because I knew I worked them harder. They were still just fine, I did not throw them out. I still have the old ones in my tool box, I will keep them as spares. I replaced my coil packs with denso coil packs. I just made sure to buy them from a reputable place to make sure they weren't fake. I've changed my plugs every 30k since

 

I put 91k on my original set of plugs and they eroded to gaps similar to yours; anywhere from 55-61. I think I've changed them twice since then

 

Be VERY careful trying to torque to spec if you use anti-seize or any other friction modifier. You'll strip 'em.

 

Two reasons I bought a taco was no timing belt and I can change the plugs myself. Copper every 30k miles.

 

Why would they use Denso's on one side and NGK on the other?

 

I believe Toyota was trying to spread the money around and keep both suppliers happy.

 

I've got 127k on mine and I keep waiting for Toyota to mention it when I get oil changes. I asked about it last time and they didn't seem too concerned but did quote me at $330 for the job. Probably should do that actually...

 

I have no idea, from what someone had said on here, toyota has done that forever

 

So, what does the factory service manual call for?

 

It's between 16-18ft lbs. I can't remember exactly. I'm all about going based on feel. The person that mentored me since I didn't have that father figure growing up to be shown stuff is use common sense for what your tightening. Spark plugs, he drilled into my head your screwing metal into a aluminum head. So, be careful.

 

I meant in terms of applying anti seize to the plugs.

the FSM shows 15 ftlbs


https://www.densoautoparts.com/spark-plug-installation/#:~:text=Finger%2Dtighten%20the%20spark%20plug,in%20extreme%20cases%2C%20engine%20damage.


Denso mentions if using thread lubricant that torque values show be decreased by 1/3.

 

Sorry, miss read what you asked. Someone can quote me if I'm wrong, but I think the values go up. Someone told me that and told me it changes the torque value. And I mentioned I used anti seize on bolts and he said careful doing that. So, I assume that's what happens. But then again, I may be wrong.

 

I pulled my factory plugs at 125k. Gaps were fairly large, but I couldn't tell a difference in performance between those old plugs & the new ones I installed. Hell, I don't think I even saw a bump in gas mileage

Now I run 50k. Figure it's a good middle ground between 30k & 125k lol

On a side note - I'm surprised and confused to see a thread like this from @TnShooter. He's one of the go-to guys for mechanical advice on this forum

 

I like to help other people.
I don't like to "help myself"......
If you know what I mean?

I don't actually like working on vehicle.
I like figure out what is wrong with them. The fixing them part, not so much.

My father was a mechanic. I got burnt out "fixing stuff" a long time ago.

The main reason I am on TW so much is, I like to help people.
And I have a general understand of Automotive workings.
So I do what I can to help out others.

 

Anti-seize acts as a lubricant.
The problem is, there is a lot more to it then that.
Thread type, pitch, material all play a roll.
Depending on the source, you use 15-30 percent LESS torque if using anti-seize.

With Anti-Seize you would set the torque on the wrench LESS.

The equation is : New Torque = Torque * percent

Example: 15*30% = 10.5

If using 30% factor 10.5 ft/lbs on the wrench
If using 20% factor 12 ft/lbs on the wrench
If using 15% factor 12.75 ft/lbs on the wrench

10.5 just isn't enough to make me feel comfortable.
Neither is 12.
I'd set it to 13 ft/lbs and call it good.

The threads in the head of the 1GR are long.
Even if you used 15 ft/lbs with anti-seize, You would likely break the porcelain in the plug before you damage the threads.