While changing out my injectors I figured it would be 'smart' to go ahead and replace the glow plugs while I'm there. On the passenger side closest to the firewall I pulled a plug out (AC 9G) that was surprizingly 3/8" shorter than all the others. I can tell that it is a recent brake, the tip lacks the nice patina of carbon buildup that the rest has. They have all come out easy, no mushrooms. The new one will go in, so I know the tip is not stuck in the hole, but I cannot see in the injector hole because of the AC box.

I fished with a magnet, and tried compressed air in the injector hole, but nothing. I have a feeling that passing a kidney stone like this would fubar a turbo or valve - right? Is it possible it's already gone and done no damage? Is it possible that this is the rattling I was speaking of in my previous topic? (ref Blown head gasket?)

Real good possibility. For some reason the Suburbans had 9G's in them well after the trucks got the revised 11G's it seems. Mine to had the 9G's but I was lucky, a couple had popped but didn't break off:cool: .

I pulled the head off tonight hoping to find the broken piece inside the chamber/cylinder but found nothing. Nothing that is but the GP next to it broken off even farther (3/4" missing off the end) and the broken end was black, giving the appearance that this happened some time ago. Both cylinders look fine, I can still see the cross hatch from the hone. Did GM plan on this and these things break down when they break off? Should I not have even bothered pulling the head to find the tip?

On a side note, I found Felpro head gaskets on the truck. I bought it with 167k miles and know nothing concerning history. Felpro is not the OEM supplier are they?

Any input would be apprieciated, thanks.

if nothing else i'm impressed after 197k you can still see a cross pattern.

167k but still impressive.
Mark

if nothing else i'm impressed after 197k you can still see a cross pattern.

GM didn't "plan" this! It cost them plenty on the warranties in the early years. The material is a sintered (powdered) non-ferrous metal. That's why the magnet won't pick it up. The material will break up but, after exposure to lots of hot/cold, it does get hard.

Sometimes, it breaks up rather easily without damage. Other time, dents/holes in the pistons. Most early 6.2's I've disassembled had shown signs of glo-plug failure by the dents on top of the pistons. I've seen lots of them that didn't hurt the driveability. Just made noise for a while until the piston "crunched up" and "spit out" the pieces.

I've experienced this while driving and before I could do anything, the damage was done. Fortunately, it was minimal.

167k but still impressive.
Mark

Actually it's 201k. I pulled the intake valves out of the head, just to be sure I wasn't missing the pieces somewhere, but didn't find anything but some carbon on the back of the valve. Would that build up on the back of the intake be due to oil from the turbo? I don't see where fuel ever see's the back of the valve. Am I correct in this?

I was also surprised not to see any valve seals. There was something at the top of the stem, right below the keeper groove. I'm unsure if it is plastic, or brittle dried rubber. What purpose does it serve?

I don't see where fuel ever see's the back of the valve. Am I correct in this?

On the way in???????????

The brittle o-ring is just that, an oil scraper ring that resides on the valves to scrape off any excess oil that will otherwise get passed down the valve stem and then . . . . . . you get that crusty deposit on the intake and exhaust valves. That is due to oil passing down the valve guide and getting burnt on the valve and then it deposits that carbon buildup. No biggie.

Just get new orings at any auto parts store. Same as a big block's I think.

What they said. ;-)

On the way in???????????

From what I see, the fuel comes in the port from the injection chamber, the air comes in from the intake valve, without fuel.

Duh, sorry was in gasser mode:duh: :idiot: :smashfrea :sorrysign

It's sometimes a hard mindset to get used too isn't it. The no throttle butterfly still seems odd.