Does anybody know how to solve this trouble?

I try to change spark plug. After I took old one out, I can not put new one in completely. I only can turn 3-4 for that one. All of others, I need turn 10-12.

Any ideas? Thanks a lot.

 

Probably you just put that one on crooked (not straight). Did you try removing it and try again?

Just my guess.

 

Well hopefully you didn't strip the threads. Very carefully try to put it back in.

 

Hi,

After I try many times, I post this thread.
Now I got a thread chaser from Autozone and a kind of "cream". I will try this cream first. If it does not work, I will try the chaser. Thanks.