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this is year specific iirc. look at daox's thread, it has some pcv info in it.

this is it (i think)

http://www.aveoforum.com/forum/f103/2005-5-spd-sedan-timing-belt-issues-being-repaired-10191/index13.html#post131817

i think there is another one on the backside of the block? i remember doax's build thread acknowledging something of that sort. Check it over.