Anti Seize on spark plugs?

[scooter122983]

A friend of mine went to the hobby shop to change the spark plugs on his car and while he was putting anti seize on the first plug a mech came over and told him not to put any on the plug. This is not the first time that i have heard them telling people this. I have always used it on my truck and my wifes car and never had a problem with the plugs falling out, as they say is the reason not to do it. One said he heard of a plug shooting out of the head at high RPM's.

 

[madmike]

I don't see any good reason to put anti-sieze compound on a spark plug going into a cast iron head, and torqued properly. Once or twice I ran into a plug that was extremely difficult to remove, but that was because some dumba** previous owner tightened them way too much.

If you're putting the spark plugs in an engine with aluminum heads, then yes, I would definitely use the anti-seize compound. It lubes the threads, and allows easy plug removal, without 'removing' any aluminum thread with the plug. It prevents galling of the threads between dissimilar metals.

 

[Leper]

Putting it between dissimilar metals can cause them to seize. I have seen it several times on Hondas with aluminium heads. I don't know if it is just the anti-seize or not, but Honda advises against it.

 

[goldwing2000]

I don't know what Honda is smoking but you should always put anti-seize between dissimilar metals to prevent galvanic corrosion. Especially something like a spark plug that has 40,000 volts going through it and is commonly installed in a vertical well, subject to all sorts of things falling into it.

I put anti-seize on every fastener that I take out, including spark plugs on both iron and aluminum heads. Iron to prevent rust and aluminum to prevent galvanic corrosion.
When I bought my new Mazda, I actually pulled the plugs out and anti-seized them so they won't be stuck in there when I go to change them at 100,000 miles.

If somebody has plugs "shooting out of the head", then there are deeper issues.

edit: just to qualify my statements, you need to use the antiseize on spark plugs very sparingly. Just enough to coat the threads lightly and be sure to not get any on the tip. Best bet is to leave the first full thread on the plug clean, that way the A-S won't run down the plug when it heats up.

 

[scooter122983]

Maybe the plugs on Hondas are getting aluminum on them because they are not using any anti seize on them. I do believe that antiseize should be used sparingly but always on spark plugs. Mercedes dealers use it always and when my friend went to put it in his Mercedes the mech told him not to. I trust the dealer personally.

 

[BadBob]

If somebody has plugs "shooting out of the head", then there are deeper issues.

edit: just to qualify my statements, you need to use the antiseize on spark plugs very sparingly. Just enough to coat the threads lightly and be sure to not get any on the tip. Best bet is to leave the first full thread on the plug clean, that way the A-S won't run down the plug when it heats up.

Ford has some some problems with that on the mod motors. You look at their plugs, and they have a foot of thread...but there's only about 2 in the actual head

Very sparingly is a good idea on the plugs. It hardly takes any anti seize to keep them from sticking. Even better: only use it every other plug change. You don't EVER want that crap getting into the chamber. It'll cause a nasty hot spot, and it doesn't burn off clean at all.

 

[JEBSR]

Well I have been using anti-sieze on plugs for over 15 years and have never had any negative results from it. However in my first year or two of being a mechanic I saw several negative results from not using it. To me that's justification enough. We ran it in my old boss's dragster and never had any plugs come loose or come out. If we shifted that at 8,600 and all the vibration of a solid mount and huge cam with no problem I dont see how that mechanic can justify that statement.

Not trying to be a smart@$$, but until someone can justify why not to use it I am continuing to do what I have seen work with my own eyes.

 

[twoslo4five0]

i always use anti seize...thats just what i have been raised up to do...

 

[Jason4x4]

I have never used anti seize on a spark plug, If the engineer of the engine designed it for anti seize, it would have it on the original plugs, but I have never seen a problem exceopt for people overtightening a plug, and anti seize can actually throw off a torque spec, if the threads are lubed, the torque CAN go up, which would throw off the heat range. but that is my opinion.

 

[Tabb]

Yes. I use it on spark plugs, not too much though, just a little dab then roll into the threads with your finger. A little dielectric grease on the tip too. I hate dealing with seized plugs and boots. I have never had a problem with plugs blowing out on anything except one time one a f@#! bronco. thats only because the old plug was seized and the threads in the head were damaged during removal, I should've used a Heli-coil but I just put some anti-seize on the new plug and put it in. I dont use it on f@#!'s anymore. I hate working on F@#!'s

 

[scooter122983]

Thanks for the input i told him to yank the plugs and put a light dab on the threads and try to keep it on the upper threads and leave the bottom one or two clean.

 

[lurtch-k20-(78-90)]

Yes. I use it on spark plugs, not too much though, just a little dab then roll into the threads with your finger. A little dielectric grease on the tip too. I hate dealing with seized plugs and boots....

I agree use it, also dielectric grease. If you can find silver antiseize get a jug of it, the heat range is around 2500*F , plus it conducts electricity better than copper, yet copper antiseize (heat range 1200*F) is still better than, Nickel based, as far as conductivity and high heat.

 

[goldwing2000]

.. If the engineer of the engine designed it for anti seize, it would have it on the original plugs...

Working for an auto manufacturer, I can tell you without question: That's BS.

#1 Engineers aren't the brightest folk when it comes to designing in servicability.

#2 Even if one of them did melt down their brain freeze enough to come up with something like that, management would shoot it down. Do you know how much extra it would cost to put a dab of anti-seize on a couple billion spark plugs? Especially when you figure in the fact that the guy doing it is making $30 an hour?

 

[Jason4x4]

Working for an auto manufacturer, I can tell you without question: That's BS.

#1 Engineers aren't the brightest folk when it comes to designing in servicability.

#2 Even if one of them did melt down their brain freeze enough to come up with something like that, management would shoot it down. Do you know how much extra it would cost to put a dab of anti-seize on a couple billion spark plugs? Especially when you figure in the fact that the guy doing it is making $30 an hour?

then why do o2 sensors come with anti seize on the threads? it doesn't cost that much, and there is a reason they put it on some things and not another.

 

[goldwing2000]

then why do o2 sensors come with anti seize on the threads? it doesn't cost that much, and there is a reason they put it on some things and not another.

Three reasons:
~O2 sensors are part of the emission controls and have to warrantied per federal law. Spark plugs in new vehicles are good for 60k-100k miles and are considered a "wear item" and rarely warrantied beyond 12k miles.
~A vehicle only has 1 to 4 O2 sensors but 4 to 10 spark plugs.
~Exhaust pipes are hotter and dirtier than a cylinder head and are exposed to more road grime.

And honestly, I don't know if factory-installed O2 sensors have anti-seize on them. None of the ones I've taken out have seemed like it!

No, each plug wouldn't cost that much to anti-seize but, like I said, multiply that by billions of spark plugs, plus paying UAW labor to put it on, and the cost adds up quick.

 

[Leper]

Three reasons:
~O2 sensors are part of the emission controls and have to warrantied per federal law. Spark plugs in new vehicles are good for 60k-100k miles and are considered a "wear item" and rarely warrantied beyond 12k miles.
~A vehicle only has 1 to 4 O2 sensors but 4 to 10 spark plugs.
~Exhaust pipes are hotter and dirtier than a cylinder head and are exposed to more road grime.

And honestly, I don't know if factory-installed O2 sensors have anti-seize on them. None of the ones I've taken out have seemed like it!

No, each plug wouldn't cost that much to anti-seize but, like I said, multiply that by billions of spark plugs, plus paying UAW labor to put it on, and the cost adds up quick.

Where do you get your info? From the Dealer you worked at for 6 months? Or are you just pulling info out of a hat?
As to your warranty statement, the plugs are covered the same as the other emission controls. Most people just don't know it. Some have longer warranties than the plugs, but they are still an emission item.
As for the cost of applying the A/S, they can build machines for that.
I have never measured the temps, but IMO the spark plug gets pretty hot, being that it is inside the combustion chamber. So I'm not sure if the exhaust pipe gets that hot. Yes, it is hotter to the touch sometimes, but the metal is a little thinner than a cylinder head.
.02

 

[goldwing2000]

Where do you get your info? From the Dealer you worked at for 6 months? Or are you just pulling info out of a hat?

As I stated back on post #13, I work for an auto manufacturer. Visteon Corporation (formerly Ford Motor Company) for the past 9 years, to be exact. Before that I built prototype vehicles for Roush for 2 1/2 years. And before THAT is when it took me only six months to figure out the dealer shops are hacks.

Oh, and I've been an ASE Master Mechanic for about 11 years, too.

So where do you get your information? Extraction from your avatar?
Why do you think they put anti-seize on O2 sensors and not spark plugs?
Do you have any facts or data to back up that opinion? Or do we just take your word that "Honda advises against it".

But you know what? You think whatever you want to think. I know the facts about corrosion between dissimilar metals, especially those carrying an electric current. You go ahead and fight with your fasteners all you want.

Have fun.

 

[ryoken]

hehe, you guys need to come work in the marine industry...

Talk about a job where you deal with galvanic corrosion, disimilar metals, etc, it's a daily thing for us...

 

[ryan22re]

I always use anti-seize on every spark plug I install. Period. That's probably thousands of spark plugs over the last 13 years. Never had a problem with any one I have ever installed. Even got it past the first thread, maybe a little on the electrode, No biggie, just wipe it off.

Don't see what the big deal is, it's just a spark plug. You can apply anti-seize based on how much you would like to remove it later on.

 

[JEBSR]

I'm going to have to disagree with it messing with torque specs. I saw the thread on that a while ago, but still can't see it happening. Every major engine builder that has put out an engine assembly book say to dip your head bolts in oil before torqueing them down. That makes them much slicker than anti'sieze will. Besides that, a proper tapped bolt hole will offer little resistance anyway. You should be able to run it down by hand. Then torque to specs. According to several of my books putting the oil on the threads actually makes the torque more accurate not less.