How do I fix oil blowing from my air breather crank case

This is classic example of blow-by caused by failure of the valve seals and / or piston rings. Combustion gases leak past the sealing surfaces causing an increase in pressure within the crankcase. It is commonly due to higher-mileage engine with less than required maintenance history (lack of frequent oil changes). To check for excessive blow-by, remove oil filler cap, then idle warmed-up engine. If steady stream of smoke emits from oil filler opening, either or both of the items mentioned need attention. Compression test and leak-down test should both be performed to verify causes and components needing service. Depending on degree of failure, it is not unheard of to keep driving vehicle while being judicious about maintaining proper oil level and air filter cleanliness.