Does it turn at all? Is your spark plug socket 6- or 12-point? Have you tried soaking it with a penetrant like PB Blaster?

 

Those spark plugs don't look good man. I think you might have a serious problem. Also, it sounds like the spark plug is seized. Try tightening it back in a little and then twist it out further. If that doesn't work, well then maybe it's better to just leave that spark plug be. If you want to continue loosening it then I'd suggest a long breaker bar. Just keep going until it's out. Don't use a small ratchet.

 

Those spark plugs don't look good man. I think you might have a serious problem.

Per his previous thread, he is battling a misfiring issue. Otherwise the spark plug look like most plugs that haven't been touched for 100K...

Spanner, I don't think he should be trying pb blaster in this situation, because it's going to get into the cylinder, and we don't want that getting into the cylinder.

Why not? It's combustible and will burn off in about 2 seconds once he starts the car.

 

Spanner, I don't think he should be trying pb blaster in this situation, because it's going to get into the cylinder, and we don't want that getting into the cylinder.

 

Agree with that. I've used Penetrene in Australia for decades. I don't know if you have it in your country, but it causes no harm to engines. I've poured it in engines that haven't been used in years so the piston rings won't score the bore. I do this twice over 48 hours.

https://www.malleeagencies.com.au/pages/penetrene-oil

 

It moved a little, but got tighter. I almost felt like something was going to break if I kept going.I'm using a 3/8" medium ratchet with a 6 point 5/8" spark plug socket.

 

Here is the troublesome plug!

 

When you try to loosen it counter-clockwise it feels like it's tightening? Obviously that shouldn't be the case, it's a standard thread like the other 5 you already did.

I'm thinking maybe it was cross threaded when it was installed so many miles ago and it's not going to thread out nicely. You can just try to apply more force and it'll probably come out but it'll likely destroy the threads in the process. Not sure what other option there is.

You probably know it's important to hand thread the plugs before you start torquing them because cross threading with the E46's aluminum head is not fun.

 

What about putting a little ATF oil on it. I doubt it will hurt anything. ATF penetrates really well. I'd put some oil on it and wait at leastan hour maybe 2. Let it penetrate. Even if cross threaded will help. People use ATF to clean engines... It dissolves burnt residue! It can reduce torque required by 20 to 30 ft-lbs.

 

Tighten it and drive the car. See if your faults are coming back. If you continue you may be pulling the head to fix the problem.

 

Don't underestimate penetrating oils and ATF oil. They work extremely well! I would not try this dry. They will only penetrate to half or 3/4 of the threads. I don't think you need to worry about these oils.

 

don't use the ratchets wrench but a solid bar (as breaker bar) instead, then just go CW and CCW, back and forth until the movement increased, but don't force it too much or it might break.

 

Do I use some PB Blaster penetrating oil and go back and forth with a breaker bar? I have a 1/2" breaker bar and my socket is 3/8" so I would need to use an adapter. Is that an issue?

It's only an issue if you're trying to torque/remove a fastener with much higher limits (think: suspension) than a spark plug. The advantage of a breaker bar over a ratchet for the kind of back-and-forth rocking movement you'll be putting on the spark plug is that you won't have to constantly keep switching the ratchet from "loosen" to "tighten" as you rock.

 

That's the right approach but make sure you use penetrating oil. Don't even try without it. I don't get why you would even consider not using penetrating oil considering the risk.

 

Cool! I will use penetrating oil. Let it soak overnight?

 

^X2
Heat + penetrating oil are your friends in general for seized parts. Good luck.

 

Hot head has soft aluminum threads!!! Beside the plug also expanded too, so gain is little but risk is high of softer threads. If you like, fire it up for 5 minutes idling, wait for 5 minutes then work.

 

First - the plug was not 'cross threaded'. If it had been it would haven been impossible to seat the compression seal on the head face. On a 'long reach' spark plug it is extremely difficult to start a plug cross threaded. If you keep trying to force it you will strip the threads of aluminum head before you ever get the plug seated.

Second - What has happened is a little bit of galvanic corrosion. A little of the aluminum head has corroded to the steel spark plug. As you turn the plug out the spot where the aluminum is attached to the plug doesn't have enough room in the grooves of the thread area above it. As you put more force on the wrench the threads of the aluminum head are deforming so the plug can turn. The aluminum on the plug and the plug itself are also deforming. This is commonly called 'galling' or 'rolling the threads'. The tip of the 'v' in the thread is getting flattened.

Three - The main danger here is breaking the spark plug. If you decide to try to remove it technique is critical. Decreasing the friction from all other sources is helpful. Back it out as much as you can and put some penetrating or 3 in 1 oil in it and let it soak. Use the longest wrench or breaker bar you have. Work the plug all the way back in and then turn it out again. Keep working it smoothly back and forth. The reason for the long handle wrench is not so much for leverage but for smoothly, gradually increasing force as you turn it out. Repeat - more penetrating oil - screw it back in then back out. As long as it does not get more difficult to turn it back in and torque it tight, keep working. Do not hammer or use sharp blows. If it gets really difficult to tighten it back up you might consider tightening it back up and leaving it.

Four - Some of the aluminum from the head is going to come out with the plug. This is not a problem on a long reach plug. There is still plenty left. What may happen is when installing the new plug you won't be able to screw it in buy hand. You will need a wrench to screw it in because the threads in the head have been 'rolled'. In that case you won't be able to use a torque wrench. Work the plug back and forth until you get it 'seated'. You will have to use the 'seat it then turn another quarter turn' method as I call it. According to NGK and Bosch if use any kind of anti seize you must use that method any way.

Lastly - this is a good example of why I always change plugs at 60k miles. Good luck.

 

Thanks for the detailed steps. Will definitely try this tomorrow and post the results.

 

Op probably get it already but if not, pb blaster is fine to use. I***8217;ve used it to change plugs on multiple cars including 2 e46s. Just be careful op!

 

Any penetrating oil will do. As said, install the other plugs, and drive the car till opererating temperature with the penetrating oil. Have your breaker bar and adapter ready, and try to work the spark plug with CCW and CW movement out. It has to come out. If the tread of the head is fubar, there are sleeve like inserts which will repair the tread in the head. Do NOT use a helicoil. Use some grease on the tap to catch most of the shavings when retapping the treads. A few aluminium shavings entering the cilinder will not harm, and will melt/burn or expelled with the exhaust gasses. This method helped me several times

 

Heating the engine is not as important as penetrating oil.
Penetrating oil makes a drastic difference.

PB Blaster sucks though. Use Liquid Wrench (by far the best! Only torching works better than Liquid Wrench... but not by much)

https://www.youtube.com/watch?v=xUEob2oAKVs

 

Great video! Thanks for posting!

 

Do you know anybody with an impact driver? It sounds like there is some corrosion as shadetreemech said. I would highly suggest you let it soak with penetrating oil and then hammer on it with an impact driver - you'll be applying less constant torque (less risk of shearing the plug) while having the best chance of dislodging corrosion. Just be absolutely sure that you don't strip the hex.

 

Bad idea of using impact driver for this. The plug hollow thread portion might break off then what? Crying?

 

lol at pb blaster sucks , it's not bad


kano kroil , get some .let it soak overnight

if it get's in cylinder it will burn off , wtf you think it's going to do?

 

For what it's worth I just had this happen. I did the pb blaster soak, and then just said "screw it" it's coming out one way or another. I was ready to see the threads of my head on the end of the plug. But, it came out finally, no damage to the head. I used the ***8220;tighten some, loosen some***8221; method. New plug went back in and it's been great ever since. It was a scary moment though. Make sure to use anti seize on the new plugs to avoid future issues (and no, it doesn't HAVE to be copper anti seize)

 

I put anti seize on the other 5 plugs I installed. Now if I can just get this one out, I'll put happy! ***x1f602;

For what it's worth I just had this happen. I did the pb blaster soak, and then just said "screw it" it's coming out one way or another. I was ready to see the threads of my head on the end of the plug. But, it came out finally, no damage to the head. I used the "tighten some, loosen some" method. New plug went back in and it's been great ever since. It was a scary moment though. Make sure to use anti seize on the new plugs to avoid future issues (and no, it doesn't HAVE to be copper anti seize)

 

Mechanics use anti-seize on plugs, but 'the book' says not too...at least last I heard. Anyway, reminds me, it's probably time for my plugs again...that or finally fix my speakers that haven't worked for 10 years.

 

NGK and Bosch both state the head should be cold when removing plugs. Yes the head expands more than the steel plug but the hot aluminum adheres to the steel better too. NGK and Bosch plugs that are already zinc plated don't require any anti seize. The zinc does the job. You can still use anti seize if you choose just be aware you need to reduce the final torque value by 30% or so. In BMWs with compression gasket plugs it will probably never be an issue. If you are changing tapered plugs the risk of breaking a plug increases significantly. Or - in the case of some well known fords the risk of 'spark plug ejection' increases astronomically.

 

^Exactly. You only need anti-seize on garbage plugs. NKG instructions say not to use it. You can... but risk over torque. I didn't bother using any. Have no plans on keeping the plugs there for 10 years.
Just use a torque wrench and you'll be fine for sure.

 

I hope you used copper based anti-seize compound!!! If you used the regular stuff you’d better remove the plugs, use brake cleaner on the threads and let them dry. Then, put a tiny dab of copper based compound on the threads and use a paper towel to force the compound into the threads. You should be able to see only a very thin line of the compound in the grooves of each plug.