I have been running a 2002 Chev K3500 w/LB7 Duramax with some smoke from bad injectors. I had to shut down engine when abruptly there was a lot more smoke pouring out of the exhaust and at the same time, occasional tappet type noise coming from the engine. Sounded like something was hitting to underside of a valve cover.
I have now torn the engine down to the point that I have removed all eight of the injectors. While removing the injectors, number 1 cyclinder injector came out freely with its sleeve remaining on the injector. I found no other evidense of anything that might have caused the "tappet noise."

Question: Does anyone know what was causing the occasional tappet noise? I know the additional smoke has obvisiously come from the leaking bottom seal around the sleeve which was identified as loose when the #1 injector was removed. My concern is whether there may be a head gasket problem too or... there may be other sleeves still remaining glued in each injector hole that may be leaking too. None are in any way loose like the #1 sleeve.

Question: Do I go ahead and replace ALL the glued in sleeves besides the injectors or is the one loose sleeve the occasional noise maker?