Spark plug won't thread...
 

Okay so as normal, my tune up went south. I was replacing spark plugs and I was in a great mood as I always am when I'm doing something on a car that's going smoothly. Cylinder 1,2,3,4 & 5 all done with new spark plugs and new coils for some. Almost done. Get to number 6 and when I pull out the spark plug oil spurs everywhere. Now right off the bat I'm thinking I'll need a valve cover gasket. I examine the spark plug and notice the little washer on it is missing and assume that was the problem considering there was no oil in any of the other cylinders. So I proceed to clean out the cylinder and put the new plug in. That's when the real problem emerges. The spark plug will not thread. I keep trying to twist it in and make no progress. I also tried to put in the spark plug that I took out of it and that didn't go in either. I have a feeling it has something to do with the oil, but realistically I am clueless. Someone please help me before I blow up my car. Thank you in advance!

It is possible that you accidently screwed the spark plug in at the wrong angle. The plug started cutting new threads in the aluminum head. This is called cross-threading. You will need to buy a tool called a tap. Buy one the same size as the spark plug. This will restore the threads so that the spark plug will screw in properly. I had the same problem on a 4 cyl Nissan pickup this past spring. The tap saved the day.

^It does sound like it got cross-threaded somehow.

How easy did sparkplug 6 come out? The same as the other five? It kind of sounds like it was cross-threaded prior to removal; meaning the last time the spark plug was changed is when cross-threading may have occurred.

Have you looked down at the threads with a good flashlight? You may discover something.

That makes sense. I forgot to mention that it did come out just a little bit rougher than the rest, but I figured that was due to the entire spark plug being submerged in oil. It didn't even look like there was a plug in it . I'll look into the tap.

The crush washer from the old plug is stuck to the head. The plugs wont easily thread into the old washer. Use a pick tool to remove the old washer from the head.

^^^^^This

and this ;)
I just tried to remove the washer from an old spark plug for the heck of it. It wouldn't budge; it just spins and I can't get it past the first thread w/o a ton of force, as I'm sure that's how they're designed. Weird how your washer stuck to the head and you were able to extract the spark plug. This probably explains why #6 was more difficult to remove than the others; you were fighting the washer.

When I read your original post, for some reason I figured you had removed the washer that was left behind when you said you noticed the missing washer and cleaned out the cylinder. Reading it again, it seems the washer was left behind as asand1 pointed out.

If #6 was drenched in oil, I think you need a new spark plug tube seal, not a valve cover gasket.

great catch & insight; very good indeed!:thumbsup:

Uh.... I did not notice the missing washer portion of your first post.


Interesting..... first time I heard of this. I keep reading this forum every day. I learn something every day.

Alright so I figured it out. I'm an idiot. When comparing the spark plug that I took out of of cylinder 6 to the others, I noticed that it was very slightly bigger than the others. Ao slightly that I was able to miss it originally. I figure at some point in time that cylinder was cross threaded and someone used a tap to fix the threading and then screwed a sleeve over the spark plug. Probably used a repair kit that my local advanced auto guy suggested after he blamed me for the problem claiming that I should not use a spark plug socket to insert the plug but instead some kind of flexible tube... Anyone agree with this guy? I thought it was ridiculous. But anyways maybe that would also explain the missing washer? Who knows. Case closed I guess. Thanks guys.

So you looked down in the tube and confirmed that the washer isn't stuck down there?

The flexible tube thing is unnecessary IMO. You can use a spark plug socket with a long extension. But, that's all you should use to get the spark plug in. Just use a long extension and the spark plug socket and install it by hand, no ratchet at this point. By doing so, you won't cross thread the soft aluminum head. With a ratchet, it's all too easy to be slightly off, use too much force and then BAM, cross threading just occurred.

I looked down and saw nothing. Everything seems fine and the plug goes in no problem with the sleeve.

Alright, sounds good. Hope it works out for you.

Thanks guys for your help and input and getting me worried hahaha

Night stalker,

You seem to have a problem. Solvable, but a problem. You mentioned that you have a sleeve over the sparkplug. I believe that you are on the right track. Someone in the past repaired a stripped spark plug hole with a helicoil or a time-sert . It has come out with the plug instead of staying in the head.

Other members: do you agree.... and how to fix this.

Start them with a 3/8" hose...If you still can't get it done swap plugs and see if it's the spark plug or the spark plug hole! Get your sparkplug thread chaser out with plenty of chassis grease to catch the chips....

The sleeve comes off of the spark plug and screws onto others. Are you saying the sleeve part should be staying in the threads of the cylinder and the spark plug should not pull that out with it?

I should have mentioned I already have the new plug in. Do you think this will be problematic in the future or something?

If the plug threads were messed up then great! But if the threads in the head are screwed up then I would chase the threads with that greasy sparkplug tap.

+1

Now there's an old hemi-head plug installation trick. I use a piece of extra fuel line hose to start plugs. It works also when you have a plug in a tight place that may be difficult to reach.

Attachment 20588

I think you may be right.
Does the sleeve look something like the (top) one in this picture?
http://www.denlorstools.com/autoblog...Comparison.jpg

Yes it does. It just screws over the spark plug.

I was right. Someone stripped out the original hole and intalled the coil thing. It is supposed to stay in the head. It decided to come out with the spark p;lug. Chances are that you need a new coil thing and install a fresh one into the head. I only have theoretical knowledge of this. I have not done this myself. Others have. General question: how to fix this?????

Well I'll cross that bridge in about 9,000 miles from now hahaha

???? you mean 60,000, right?

Install the new helicoil with high strength locktite!

If the new plug with the coil on it wants stay in the head you are good for a long time. If you used platinum plugs that is 60 k miles. Best wishes!