Its a Mazda 323.first it was leaking oil from the oil switch.we put a new oil switch.now it started leaking from oil filter.then we changed the filter again it reverted back to oil switch
Sounds like you have a high oil pressure problem. Check your PCV and hoses for a blockage.
Connect an oil pressure gauge if you can. But I'm generally in agreement with Tom. It sounds like the PCV system has a blockage.