Tom,

I was hoping my Indy could do a compression check for me, and didn't have the right fittings 8(. He returned the car with an injector return line leaking
8( 8( 8( . I just replaced a couple of the return lines tonight and have a small pool of diesel on the base of 2 injectors. I noticed the bubbles coming from the base of the injectors also. I think I have fixed the return line leaks, but I was too messy to get into the car and drive it and evaporate the diesel. I'll let you know in a day or so if the bubbles are still there.

My hypothesis... it appears there is a small vent hole of some type at the base of the injector where it screws into the head. Note the base of the injector is flush against the head for 355* of the injector base, but there is a small section that is purposely curved inward along the outside diameter. I'm guessing it is some kind of vent to allow air to move in/out while the injector moves.

Anyone else have a better idea?

Chuck