Breathers do give problems often because of sludge buildup. Regular oil changes are the answer. Yes, torquing the head bolts is important and always use a new gasket.Refer to a shop manual for correct torque values and sequence.

In addition to torquing the headbolts pay attention to the sequences in which they are tightened.

A clogged breather in some engines can cause oil to leak out anywhere it can due to elevated pressure in the crankcase from 'blow-by', which is present to some extent in all engines.

Thanks!