random oil leak

[matthg40]

hi guys sorry that all my posts seem to be problem posts.erm i changed the head gasket about 3 week ago built the engine back up all seemed well, but now i have a random oil leak coming from the back of the block.now i assumed it was the rubber o ring that holds the dipstick houseing in the block. so i changed it,it stop leaking now its leaking again any ideas anyone cheers

[hayesey]

the oil breather?

[matthg40]

ah could be ive removed the boost return i could of knocked it when stripping the engine cheers dude although i have checked that hummmmm