mushroomed...
My old glow plugs were a combo of original 11G's and a few brand new,but very DEAD Champions..only one I failed to get out was the front one on the passenger side..it unscrewed ok,but the tip,it must be mushroomed pretty good..
I try every now and then after a good run on the highway to get it out,but so far it only comes out about 1/4" after its unscrewed..several of the others were difficult to remove too..took lots of carb cleaner,penetrating oil,and patience,along with lots of swearing and spinning them to get them out!..
I'd rather leave it than break it,and have to buy new injector lines and pull the intake the replace them..mine are a bit rusty,and will live many more years IF I don't molest them..so far its never failed to start with the 7
AC G60's I did manage to get installed!..and I have only used the block heater once when it was -10 last winter..
I bet I still could have gotten it started,even below zero----but have you ever heard a 6.2 thats been started without being "plugged in" at that temparature????...sounds like all 8 pistons are an inch too small for the cylinders!..CLAK-CLAK-CLAK-CLAK---

mines a stonecrusher until it warms up....
