Contour Enthusiasts Group Archives Forums General Troubleshooting Sparkplugs Un-Screwing themselves?

A few months ago my car had been misfiring. It turned out to be the ignition coil, once I got that replaced the car seemed to run fine, but, a few months later, while I was driving my car began backfiring, I pulled over and noticed that a sparkplug was loose, I replaced it, but the next day another plug came out (different cylinder). After this, I replaced all plugs making them quite tight, about two weeks after, I checked all the plugs and they seemed to be just as tight, so I forgot about it but tonight while driving, about 3 or 4 months later another plug came out, it is the same plug that came out first last time, however this time I could not get the plug to sit.

So my questions are�.

Does anyone know what would make the plugs unscrew themselves?

And

If the plug cannot get seated, does this mean it is stripped, if so how can it be rethreaded?

Thank you for any response!

The plug holes in the aluminum heads are probably getting stripped. This is why we should always use anti-seize and a torque wrench while installing them.

Thread repair inserts are available but the heads are usually removed for the repair.

I have had plugs not seat because of the welding of the hook electrode interfering with the threads. You could have stripped threads, I hope not! If you have a Duratec, try APP764 Autolite plugs. Thread in by hand on socket extension, seat firmly but not brutally with short wrench.

I have a Duratec, and have been using the Autolite plugs. also I ran i sparkplug re-thread tool through today and that went through with ease, however the plug still did not seat itself, i tried two new plugs, both did not work, also the old plugs electrode was crushed, the haynes manual says that this means there is some sort of object in the engine, and i guess that could have done something, i will try to post a picture of it, any other ideas anyone?

thanks for the replys!

Here are a couple of pictures of the plug that came out

It looks to have been hit pretty hard



It is sort of hard to see on this picture, but part of the ceramic stuff is gone, I bbelieve that that peice is probably in the engine, if i have reason to believe otherwise please let me know, hopefully these pictures can help!

That can't be good... Good luck !

the piston head is hitting the bottom of the plug?!

What plugs are you running? The Autolite Copper Core 764?

They should be APP764 Autolites for the Duratec.
Could you be melting them? Probably not.
They should say Autolite Double Platnium with the part number on the ceramic.
The shape looks correct against mine.
I see by Pic #2 you have Autolite 76xxx......

yes, they are the copper core, the black residue is also concerning to me, not sure what that is! i also changed the wires when it was misfireing, i supose that could be what is leaving that

Ok, im thinking I may take the head off, for two reasons, to get this sparkplug to seat it self and i also think there is stuff in there hitting the plug, i looked in the Haynes manual, and it dosent look too bad, so my questions now are...

is their anything eles i should do while it is off?

where can i get the re-thread kit?

should i take the other heas off to, and clean that, as it will be easier b/c the manifold will already be off?

and

Is their any cleaner i should use, i think there will be some carbon build-up as the engine has 120000 miles on it, or what do you recomend to clean it?

Thanks for everyones help!