I took the plugs out of my 94 LT-1 today. They were tight all the way out. I have (2) that will not thread in...get about a half turn and they get tight. I am afraid of turning them with a wrench because of the aluminum threads. Has anyone used a thread chaser to clean out the holes? If so, did you have any success? Any other ideas? I am putting them back in with anti-seize, but once you mess the threads up, it's over

 

I keep a thread chaser made especially for spark plug threads in my tool box. It was available at a corner parts store (in California, Kragen or whatever). I make it a practice to carefully chase the plug threads any time I feel the hint of tightness. I also always use a small amount of anti-seize on the spark plugs, header bolts, intake bolts. It doesn't last a long time on the high-heat areas but it can't hurt.

 

were the plugs changed previously? just wondering why they were so tight. I have never changed mine on my 95 and am worried about this very problem. I only have 33K on the car but have been thinking about removing them to prevent them from completly freezing.

 

No...and that is part of the problem. We are the second owners and it only has 50K on the car, but it is 13 years old. They were all tight coming out, and I am putting them back in with anti-seize. I have two that will not go back in. I'm going to try a thread chaser today. Hopefully it will do the job. I don't want a plug change turning into a cylinder head removal