first of all hi to every one

i have just bought myself a 2.0 ecotec omega t reg from my local auction house on the spur of the moment as it was to cheep to be true. well i get it home and discover it leaking oil badly from the front n/s of the engine so i seach for a forum and find you guys anyway searched the forum and decided it might be the breather system and cam cover gasket. so replaced main breather pipe at n/s of engine as it was blocked and very rusty next changed cam cover gasket as there was some oil in the spark plug wells,and cleaned the breather pipes at the o/s of the engine but its still got a leak it seems to be coming from behind the power steering pump, oil presure switch and dipstick do not apear to be leaking ,is there any thing else in that area that might be at fault,i have cleaned the whole engine but i cant find where its leaking from as there is too much in the way,and it only starts leaking at full temp any ideas please...

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