oil into plugs vaxuall omega 2.5?

do you mean oil is getting into plug holes [external] if so may be cam cover/cam carrier housing gasket/seals leaking,oil filler cap not sealing correctly....

k
August 2013

you don`t mention if it is a high mileage motor,is it burning oil on acceleration?It may be drawing in oil through your breather system via the manifold,another source may be valve stem oil seals.Also check the oil level is correct.I would remove plugs and clean them or replace if worn and re gap them.A compression test may be worth looking into also.Good luck

cdc
August 2013