Does anyone know how hydraulic lash adjusters bleed the air out of themselves? The type i'm specifially asking about in this case reside in the head. The rocker arm sits between the lash adjuster and the valve stem, with the cam pushing down on it. Chrysler 2.2 and the Mitsubishi 4G63 are two examples that come to mind.

I know that there is a ball and sproing check valve inside, and that pushing a small wire down the hole inteh top will unseat the ball, allowing you to compress the lifter. I had to do this today as i put in a new set of cams in my 4G63. After 10 minutes of idling at 1500 rpm the liters were still ticking.

HLAs constantly leak around the edges of the piston (this is a necessary part of their function) and I would expect air bubbles to escape via this path if the piston is facing up.  If the piston isn't up, I'm not sure how air bubbles could get out, because the body is usually a single solid piece.

Many hydraulic valve lifters have specific storage and installation instructions for the the lifters to allow them to initially bleed down properly prior to initial engine start.  I'm not familiar with your specific engine but did you check the factory service manual for any installation specifics?  

Usually after the oil gets good and hot and up to full pressure for several minutes at normal operating rpm's they self bleed.  I've not found it to be the case but others have reported that an oil change with a new oil filter and multi weight oil tends to quiet them down a little faster after replacement.  The viscosity of fresh multi weight oils
tends to be at its lowest point when new so that would make sense.  

It's kind of funny but in my water cooled inline 4/5 cylinder VW's and Audis with hyrdraulic lifters, I can tell with great accuracy if the oil is below full by any amount depending how much the lifters clatter on cold start.   

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