I've seen some comments about how some people have to deal with seized spark plugs on their vehicles. I'm not surprised -- if the engine block is aluminium and your spark plugs are made of steel or some other metal, you're going to get dissimilar metal corrosion and seizing. Having worked on aircraft engines, normal and round (the ones that mark their spots on the tarmac), I learned long ago the solution for that. Just put some of this on the threads, all around. End of problem.

https://www.championaerospace.com/pr...read-lubricant

 

For those of you wondering, it's not grease and it has no copper. It's a graphited lubricant, very fluid. Recommendations for use are: Apply sparingly to second and third threads. Do not contact electrodes as it could short out the plug. Do not apply to shielding barrel threads.

 

Good idea, just did my plugs today, they were pretty stiff coming out I was worried about one of them. They did not appear to have been anti-seized going in but it was hard to tell after 75k.

The new ones went in pretty smoothly so I think the threads are fine.

But google your new plugs to get the proper reduction in torque value for use with with anti-seize. 25% reduction is a good round number.

Also... if a plug is really stuck and you already tried penetrating oil you can try running the engine for a minute or two to warm it up (then let it sit for a few minutes). The aluminum head will expand more than the steel spark plug, hopefully loosening the plug a bit. CAUTION: this is a last resort, only go there if you're pretty sure you're about strip the threads with the motor cold. Reason being aluminum also gets softer as it heats, so you're walking a fine line between expanding and softening the aluminum. Running the motor briefly will heat it up a little but hopefully not too much. Don't use much force, if this is going to work it won't take much. Maybe better to just drive the car to a mechanic, but it's worked for me before. Also wait for the motor to cool all the way down before you torque the new plugs.