USE DIELECTRIC GREASE ON SPARKPLUGS

matreyia

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Apr 19, 2017
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Hello All, I am posting this short note because this has been happening far too often in regards to spark plug installation. People are asking for diagnosing misfires related to spark plugs and after numerous posts, it turns out that they are not using dielectric grease when they install their plugs.

Please apply a thin layer of dielectric grease all around the ceramic part of your plugs before installing them. They prevent arcing and misfires. This is recommended on stock coils and plugs, so you KNOW it is mandatory on BimmerLife and PR Coils. If you don't do this, you most likely will develop misfires and potentially damage your coils and plugs due to the electrical arc pathway.

Clean the metal tips and coil collars before installing to be sure there is no film interfering with the coil innards and the plug metal tip. When you remove the coils next time, it will come out much easier so that is a plus.

Cheers.

VT
 
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Jeffman

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Jan 7, 2017
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Hello All, I am posting this short note because this has been happening far to often in regards to spark plug installation. People are asking for diagnosing misfires related to spark plugs and after numerous posts, it turns out that they are not using dielectric grease when they install their plugs.

Please apply a thin layer of dielectric grease all around the ceramic part of your plugs before installing them. They prevent arcing and misfires. This is recommended on stock coils and plugs, so you KNOW it is mandatory on BimmerLife and PR Coils. If you don't do this, you most likely will develop misfires and potentially damage your coils and plugs due to the electrical arc pathway.

Clean the metal tips and coil collars before installing to be sure there is no film interfering with the coil innards and the plug metal tip. When you remove the coils next time, it will come out much easier so that is a plus.

Cheers.

VT
Agreed!
 
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Narcosis

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Truth spoken here. I didn't apply it to my new plugs when installing the PR coils, the result is evident:
 

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doublespaces

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How much is too much? I have a persistent cylinder 5 timing correction (-6-7) and it seems like it's always been there. Did it with stock BL and PR coils and I've got index 12's which only have a few thousand on them.

I'm not opposed to changing the injector again but figured I'd check everything. My resistance on that coil plug is 0.028
 

Jeffman

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I’d also check the torque on that plug. I recently had a misfire on Cylinder 2. I thought it was my PR coil going bad and purchased a new one. After removing the coils thought I’d take a look at the plug and the damn thing was only finger tight! Put in a new one which had dielectric grease slathered on the insulator, torqued it down to 23Nm, replaced the coils and all is good to go. No more misfires. Now I have a spare PR coil too!
 
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Asbjorn

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I’d also check the torque on that plug. I recently had a misfire on Cylinder 2. I thought it was my PR coil going bad and purchased a new one. After removing the coils thought I’d take a look at the plug and the damn thing was only finger tight! Put in a new one which had dielectric grease slathered on the insulator, torqued it down to 23Nm, replaced the coils and all is good to go. No more misfires. Now I have a spare PR coil too!

Exact thing happened to me last week as well. Cyl 2 only finger tight.. misfires disappeared after tightening it.
 
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matreyia

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How much is too much? I have a persistent cylinder 5 timing correction (-6-7) and it seems like it's always been there. Did it with stock BL and PR coils and I've got index 12's which only have a few thousand on them.

I'm not opposed to changing the injector again but figured I'd check everything. My resistance on that coil plug is 0.028
Just a thin film is enough. I lay down one strip of grease along the ceramic and then use index finger and rotate the plug to smear that line all around the ceramic cylinder. Carefully filling all ceramic surfaces but avoiding metal parts.
 
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Jeffman

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I agree. “Slathered” may be a little too much (I was exaggerating lol). A film of dielectric grease around the insulator is sufficient.
 

matreyia

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Exact thing happened to me last week as well. Cyl 2 only finger tight.. misfires disappeared after tightening it.

Yes, even when you torque plugs properly, they do come loose in some instances and need to be rechecked to be sure they are still tight. God help anyone who uses anti-seize on the threads on these engines.
 

NoQuarter

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Same here... Did some maintenance, happy with the results. Couple weeks later running like sh$t and it hit me... "what the f$ck now!"

Checked the plugs and 3 of them were loose. These days I go back a week or so later and re-torque any new plugs
 
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screaminfast

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Same here... Did some maintenance, happy with the results. Couple weeks later running like sh$t and it hit me... "what the f$ck now!"

Checked the plugs and 3 of them were loose. These days I go back a week or so later and re-torque any new plugs

That's smart and probably something people don't do often enough. On a brand new product, chances are there is some spring to the material, so doublechecking the torque is a good idea.
 

Jeffman

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Yeah, and since plugging in the PR coils have been “iffy” and more hassle than the OEM coils, it’s no longer quick and easy to tighten the plugs.
 

Rob09msport

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Yes, even when you torque plugs properly, they do come loose in some instances and need to be rechecked to be sure they are still tight. God help anyone who uses anti-seize on the threads on these engines.
Agree hundred percent I have multiple times found loose plugs first time I changed coils and almost did injectors cause of misfire. I felt real stupid when my spark plug basically fell out. Thank God I didn't get a nice ding on my hood from projectile spark plug. Usually that means damaged threads at that point to.
 

langsbr

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I wonder if it's the opposite - the misfires causing the plug to loosen. It's a notorious issue on the Honda J motors, as well as some of the Ford modulars in trucks. They get so loose as to blowing out. I bought an 04 TL that it happened to - it had blown out so hard it ejected the coil (which is screwed in) and dented the hood. It's usually the cylinder in the middle of the bank, front or back. The Js have an integrated exhaust manifold and that is usually the cylinder to detonate first, which is what makes me think it's detonation/misfires causing the spark plug to loosen.
 
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Narcosis

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I’d also check the torque on that plug. I recently had a misfire on Cylinder 2. I thought it was my PR coil going bad and purchased a new one. After removing the coils thought I’d take a look at the plug and the damn thing was only finger tight! Put in a new one which had dielectric grease slathered on the insulator, torqued it down to 23Nm, replaced the coils and all is good to go. No more misfires. Now I have a spare PR coil too!

I also had this happen, more than once. Attention to detail is a good thing.
 

Itsbrokeagain

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I have to do this to my clients car, we keep getting an odd #2 misfire on e85 and the last time I checked it was finger tight as well, and had a lot of dirt/soot around the bottom of the insulator. Guess I'm going to be changing all the plugs while I'm in there.
 

fmorelli

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If you are running plugs with the aluminum crush washers, beware, as I'm unconvinced they work as designed for multiple installations. The copper washers should be fine. Also two other suggestions -
  • Make absolutely clear the bottom of the spark plug shaft is clean, on the face where the spark plug mounts. It is easy for carbon or grit to be there and mess up the mating of the washer face to cylinder head.
  • Rechecking the torque after some brief use is a good idea ... that falls under shit happens.

Filippo
 

Rob09msport

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Def need to check seat I had my cyl 6 coil rubber blow wide open on the way home from mpact and got misfire under low rpm load. I figured n54 life but it happened again last night in pouring rain my coil was lifted few inches. So I popped it on and then drove home first boost it did it again so I pulled plug and it looks almost like the ceramic was leaking compression. These were zr5tpp33s plugs. Anyway I drove to 3 parts stores to piece 6 95707 plugs gapped to 25 and pulled rest plugs in pouring rain. They all seemed little slippery from the dielectric but I had ton of oil on 3 or for I cant remember cause was raining out. Anyway pretty sure that's from oil change the shop hopefully spilled oil cause my head ports are blocked and new vcg and valve cover. I was running no engine cover but had cowl on so idk at this point any ideas are welcome. Has anyone seen a plug leak compression?