My fiance's '02 escape keeps spitting a spark plug. The first time time it did it I looked at the threads on the spark plug and they looked stripped. So I figured the mechanic that did her last tune up stripped it when putting it back in and thought that's what caused it to come out. So I got a tap and rethreaded the hole, installed a new spark plug, and then everything seemed fine. Well that lasted about a month and it spit it out again 2 days. Any ideas?

 

You can't really rethread, all your doing is straightening out the threads by recutting and removing more metal. No contact area and it won't stay tight.

 

This is not uncommon on the Triton motors but I never heard of it on a Zetec. Timesert makes a kit for repairing this so I guess they have heard of it.

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sounds like an obvious damaged thread issue, assuming you are installing the right sized plug. Do the plugs torque down properly when you install them ?, if they torque down properly then the plug shouldn't spit back out at a later time.

 

Make sure you use anti-seize on the threads.

 

I believe anti-seize is used on threads so they come out easy which isn't the problem here.