The plug is about three threads from coming out, but has reached a point where it's just squeaking and going nowhere. I put some penetrating fluid on it and screwed it back in, then tried backing it out. Still stuck in the same place. Any suggestions? Thanks

Is the engine at operating temperature?
This generally makes it easier to extract/break the carbon.







Have a great day.

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Yes, the engine was at operating temperature when I started the job. I just tried another plug, and it got stuck at the same point as the first one.

carbon buildup in the prechamber. just gotta keep at it, if you can try to pry out as you turn. the threads are already all the way out, or it would still be pulling itself out.

now, you may want to ream the GP holes w/ a GP reamer tool before re- installing, or at least in the near future.

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In one of the threads some of the members said they felt that Marvel Mystery oil had some effect in dessolving carbon.
Do you have the 80003 standard loop type glow plugs or the 80035 18mm threaded pencil glow plugs?
On the smaller type pencil glow plugs I had a similar experience; I had to grab the glow plug with a vice grips and pull while working it back and forth (it was stuck but backed out past the threads). When I remove it I found that it had a swollen tip (Autolite and in the engine for only 3 months). I replaced all.
If you are up to removing the injectors you could spray some penetrating/Marvel oil onto them from the inside. (After you pull the plugs and before everything is put back togeather crank the engine over a few times incase there is an excess of penetrating oil in the cylinder to get rid of it.)

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84 300D, 82 Volvo 244Gl Diesel

Thanks for the responses. These are the older loop style plugs.I put some anti-seize on the exposed threads and tightened them back into the block. I'll take the car out for an Italian tune up sometime in the next couple of days, and try to get the plugs out right when I get home.

careful you don't burn your fingers! I didn't even bring the car all the way up to running temperature, just let it idle for about 5 minutes, but I never touched the glow plug until it was nearly out and I went to use my fingers for the last couple of twists and it was WAY hotter than I expected.. didn't raise a blister or anything, but yours might after an italian!

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