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06' C230 Sport
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Discussion Starter #1
its simple. question is: "do you apply 'anti-seize' when replacing your spark plugs?"

i have extensively searched forums to find this out. people's responses are about 50/50... and its quite controversial if i might add. opinions differ.
some folks say no because; bosch spark plugs already have the anti-seize plated on the thread, because with anti-size you can over tighten your plugs, and the anti-seize can increase spark plug temperature causing spark plug failure.
others say yes because; obviously avoids unwanted sparkplug issues, aluminum heads on MB engines, and some say they do it out of pure tradition.

What do Mercedes techs do?? do they apply anti-seize when changing plugs at the dealership??


Im doing my plugs this weekend.
My engine is: M272. my owners manual calls for sparkplugs: Bosch YR7MPP33

now, according to the WIS instructions, there is no call for anti-seize to be applied to thread upon spark plug assembly.

and according to Bosch, my plugs are no 'pre-plated' with the anti-sieze. the bosch tech guy also said to apply a dab on thread, spread evenly and tighten plug according to manufacturer's specs.

which leads us to the initial question: "do you apply 'anti-seize' when replacing your spark plugs?"

Thanks!!
 

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'07 GL320CDI
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You've got information from Bosch and from Mercedes saying don't do it.

Are you looking for a redneck shadetree mechanic's point of view or what?

PS: don't put it on your lug bolts either.
 

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06' C230 Sport
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Discussion Starter #4
and according to Bosch, my plugs are no 'pre-plated' with the anti-sieze. the bosch tech guy also said to apply a dab on thread, spread evenly and tighten plug according to manufacturer's specs.

I called Bosch directly and they said, yes, to go ahead and put a bit of anti-seize.
 

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1959 220S cabriolet, 1983 240D original owner, 1999 E300 turbo diesel, 1988 560SL, 2003 SLK320
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3,513 Posts
Torque values for spark plugs and lug bolts and everything else I think in the Mercedes WIS is given as a dry torque, i.e. no anit-seize.
 

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99 E430, 01 E430 Sport, 00 SL500
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To anti-seize or not to anti seize, that is a 100K-mile question. You don't know the answer until 100K miles later if you still own the car.
Hint: When you go buy spark plugs from any parts store, the clerk will offer a $1 anti seize packet.

>>the anti-seize can increase spark plug temperature causing spark plug failure.
That is big fat lie because anti seize can't generate heat. The temperature of anything attached to the engine can not be hotter than the engine itself (thermodynamics law).
How to apply anti seize? On new Bosch Oxygen sensors, the anti seize is not spread evenly on the threads by the manufacturer, just a "dab" because when it's turned, the anti seize will spread. Spark plugs are smaller, just a tiny bit will do. Too much can damage the threads.
So "do you apply 'anti-seize' when replacing your spark plugs?"
Yes.
I also used a q-tip to apply a little bit of silicone grease inside the spark plug boot. Now that can be another controversial question.
 

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2002 honda civic (sold), 2009 Mercedes ML350
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well as i am a mercedes benz tech, i dont apply anything to the threads. i install the plugs and yes i do torque them to the value that is supplied in WIS. if they are torqued there should be no issues
 

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06' C230 Sport
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Discussion Starter #8
great responses everybody!! :)


i think ill go with the mercedes tech's response.


however, if the plugs seem a bit 'stuck' at removal, then i might consider putting just a dab at them.

and yes, my car has 99,000 miles on it (im a realtor and drive all day) so its in dire need for plugs.

Thanks!!
 

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04 SL500 / 06 ML 500
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It's electrolysis I worry about. The current can cause a chemical reaction between the Aluminum and steel in the plugs. I use anti seize to stop the corrosion effect caused by the electricity.
 

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2001 E320 - Brilliant Silver/Ash: 107,000+
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You asked what the MB dealer techs do and Streetglower told you what he does. I think I would follow his advice. Since he's the only one to respond, it makes me wonder if he is in the minority or the majority. But couple that with the advice from MB then that's the proper method.
 

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what tha? lol.


I cant believe something so simple has me so worried...
well, my answer was controversial in itself, so I edited my post.
I do not recommend it either, and for a reason I believe it is not safe for the O2 sensors and catalytic converters. keep in mind, some if not most of the grease applied to the threads will get burnt off by the combustion flames, which means that burnt off grease will exit the cylinders and head down the exhaust, which so happens to house the O2 sensors as well as catalytics. and AFAIK, any metal particles(inlcuding aluminium in the anti seize grease) in the combustion chamber that exit out the exhaust, will damage those components I mentioned. Thats why we dont have leaded gasoline or high ppm phosphorus, moly and zink engine oils anymore.
 

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99 E430, 01 E430 Sport, 00 SL500
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In summary, keep in mind 3 things:
1. Every clerk at auto part store offers $1 anti seize when you buy the spark plugs. The store don't make any money selling $1 item to you.
2. To anti-seize or not to anti seize, that is a 100K-mile question. You don't know the answer until 100K miles later.
3. The person who does not use anti seize will not be the person who remove the spark plugs 100,000 miles later.
 

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as long as you ensure that both threads are clean and torque the spark plugs to specs, and if you use common sense when removing them, there is no need for anti seize paste.
 

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Outstanding Contributor - Always Remembered, RIP
Zotye Auto 1.5T T600 2016
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I agree with Streetglower and I too am an MB Tech.
 

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well, my answer was controversial in itself, so I edited my post.
I do not recommend it either, and for a reason I believe it is not safe for the O2 sensors and catalytic converters. keep in mind, some if not most of the grease applied to the threads will get burnt off by the combustion flames, which means that burnt off grease will exit the cylinders and head down the exhaust, which so happens to house the O2 sensors as well as catalytics. and AFAIK, any metal particles(inlcuding aluminium in the anti seize grease) in the combustion chamber that exit out the exhaust, will damage those components I mentioned. Thats why we dont have leaded gasoline or high ppm phosphorus, moly and zink engine oils anymore.
the threads from the plugs are not in the cylinder, the only thing sticking out of the head is the base of the plug, the threads dont stick out so nothing is going into the engine. besides its takes a hell of alot of any substance to do damage to the cats or o2 sensors. you could drop a teaspoon of antiseize into the cylinder and the temperature alone would burn it off.
 

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2008 E320 Bluetec, 1988 560SL totalled unto death). 1997 Dodge Ram 1500, 1983 300CD
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I do it

regardless of the advice from some constant posters. Just because the dealers/factory do not recommend it that does not make it harmful. To my knowledge, MB factory does not recommend AGAINST.

From an engineering aspect, it only makes sense to do so. We are threading a steel plug into an aluminum hole. Anticorrosion measures are appropriate. Small differences in apparent torque will matter only to those desperately anal and the possibility of a plug blowout is extremely remote. If a blowout occurs it will be because the threads were previously damaged, probably from not using antseize.

To expand slightly, the notion of leaving a spark plug in place for 100k miles (a period of 10 years for many) is absurd regardless of whether or not the factory says it is o.k. to do so. The cost of removing corroded-in-place plugs and refurbishing the cylinder head at the end of that time will be on the owner's head, not MB's. It is my practice to remove the plugs, inspect for combustion quality, clean, set, clean threads and replace with a new thin coat of neverseize once per year.

Ready to recieve incoming rounds.
 

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2007 E350 4Matic P2; 2008 GL320 CDI P2
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Just a little.
Probably not needed on clean threads in the head and a new 'quality' plug, but as a shade tree mechanic, I can not guarantee perfectly clean threads.

Only a dab, brushed into the root of the threads. No need to have enough to cause any to ooze out.

Use a Quality anti-seize, that is metal based. That eliminates the possibility to isolate the plug and cause it to overheat. (The head is the heat sink for the plug.)

Torque carefully,m since you will be applying slightly greater force to the threads since you are lowering friction.
Some say to drop the torque about 10%.
 

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The factory does sort of recommend against using anti-seize. They state that all torque values are dry torque values. Also AFAIK the recommendation to change the plugs is 100,000 miles "OR" five years. At least that's what my book says. Anyone who leaves their plugs in for ten years is asking for trouble.
 
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