I have a spark plug that is seized. It has been sprayed with w40 and ran to heat it up. I don't want to over do it in fear of breaking it.

I need some ideas.

In case I do break it into pieces, what's involved in removing the stuck part? Does the engine need to be yanked for it to be drilled out? It's twin 454 Mag MPIs and it's the starboard #5 cyl. This means it's located near the centerline of the boat.

What are some good estimates on getting that done? $200, $500, $1000? Just weighing my options.

maybe some penetrating oil would do the trick. You can pick it up at any decent auto parts store or even Walmart. The best is called something like PB Blaster or PB blast. Be careful if you have aluminum heads. Replacing the plugs while the engine is hot can strip the threads in the head.
Oh and when you do get it out, try putting a bit of anti-seize on the threads of the new spark plugs before they're screwed in.

Good Luck

soak it with pb parts blaster penatrating oil. use a round 1/2 dia punch to shock it if it won't break loose after soaking overnite. don't worry about breaking the ceramic part. id just try to muscle it out with a 1/2 drive ratchet and a good six point socket before shocking it with the punch. good luck

If it breaks and only the insert comes out you can use an easy out to remove the rest of the plug. It's really not that big of a deal if you have access to it. A little heat also helps but be carefull if the center insert comes out, the torch could ignite gasses in the cylinder and blow dust and rust into your eye. Happened to me.

Thanks everyone. I'll give the pb blast a try first, then move on from there.

Thought I heard somebody say oil???

When you have a cast iron cylinder head, you can use penetrating oil to loosen the spark plug. If you have aluminum cylinder head, the steel spark plug threads may bond with the aluminum cylinder head. Spark plug threads that are made out of steel have the potential to engage with the aluminum cylinder head properly, if they are installed properly. If they are put in without anti-seize compound, those threads can actually weld together with the aluminum, making it difficult to get the spark plug back out.

If WD-40 x 5 treatments (1/30 minutes) won't work this stuff more than likely will....

http://www.rustreaper.com/ccp51/cgi-...aff=&pg=splash


Test results:
http://www.rustreaper.com/ccp51/cgi-...test_penetrate


Now back to my lubrication home..

This is a trick I've used to get things like that out:
If you have access to an air impact gun, and a small inline regulator, connect the regulator near the gun, and dial the pressure down low. Set the gun to loosen with the spark plug socket on it, and hit trigger. With the pressure low, you should get low impact,to coax the plug out. I've broken many a bolt loose with this method, including spark plugs. You can control the strength of the impact with the pressure regulator. This is provided you have the room to get the gun in there. I wouldn't do it with aluminum heads though. It sounds nutty, but it works.

I'd have to agree on the PB penetrating oil. I've tried them all and this stuff is definately the best.

Bingo! I was about to post the exact same think, but I'd spray it with pb blaster first. That stuff really works. It's the hammering effect that breaks it loose. Just don't hammer so hard it rounds off the bolt on the plug. Been there, done that. If you do happend to round it off, take the next smaller impact socket, and drive it on the plug. If it rounds it off, go to the next smaller size.

If you end up putting heat to it with a torch, make sure there are no gas fumes in the engine compartment.

Someone mentioned this in a thread some time ago....the thought stuck with me