84 gmc 454 v8 has spark plug broken off in engine block


All porcelien on plug is gone. How do I remove plug? It looks like whats left of the plug has become one with the block. Can anyone advise? Thanks!!


Spray penetrating oil (liberally) and let it soak. Repeat several times over a period of days if necessary. Then slowly try to turn the plug with a spark plug wrench. When it starts to turn, apply more penetrating oil and work the plug back and forth. Patience is the key here.


[b]Try taking a propane torch and applying the flame directly onto the broken plug. Let the plug get good and hot. Let the plug cool back down and then try removing it.

Sometimes heating up a siezed threaded component causes the component to expand. Then when the component cools back down it contracts enough to break the bond at the threads.



I don’t understand the problem. The porcelain has NOTHING to do with the spark plug being retained. When I can’t get the spark plug boot off, when it has become bonded to the porcelain, I INTENTIONALLY break the porcelain part off. If you can’t sit a socket down far enough to remove the spark plug (it’s metal), you might need to use a small hooked probe to remove pieces of broken porcelain. If you can get a socket to sit on the spark plug hex, and it’s too tight to remove, use a penetrating fluid like PB Blaster, WD-40, etc.


Thanks for the advice!!