GM-GMC: 6.2 glow plug reamer source, combustion chambers, combustion chamber

Question
Mr. Jacobsen: I am attempting to revive an '85 Suburban 6.2 diesel. I have 2 bad glow plugs and was lucky enough to get them out in one piece (each). What do you use/suggest for a glow plug reamer since these engines have prechambers and this engine is very hard to start(guessing a lot of carbon buildup)? I didn't know if this was a GM-specific tool, not finding any listing in Snap-On,etc. Thanks in advance(and happy holidays!), Mark

Answer
I have never seen a 6.2/6.5 with carbon in the pre-combustion chambers.  There has been no reamer made for cleaning the pre-combustion chambers.  If you want to remove the non-built-up carbon, the cylinder heads have to come off and the pre-combustion chamber caps removed since the caps are pressed into the heads and are only accessible with the heads removed from the engine.

More likely, you have a set of OEM glow plugs that swelled at their tips.  I found this to be the case with the 6.2s in my 1983 G-20, my 1984 K-2500, and it will likely be the same on a 1985 Suburban that I just purchased.