After replacing the oil seals, oil started coming our from the valve cover ventilation
Excessive oil consumption and leak
The tell-tale sign of a valve cover gasket that has lost its seal is an oil-covered valve cover or a burning oil smell when the engine is running. As oil leaks from a valve cover, it can contact a hot exhaust manifold and burn. A valve cover can leak oil while the engine is running, but not while the engine is at rest.
What causes oil to leak from a crankcase through an air filter
The oil doesn't leak from the air filter rather it would be right if we call it from the crankcase this is intentionally done so as to release excess pressure from the crankcase because of blow by that allows exhaust gases to seep through piston ring gaps it continuously fills up the crankcase with huge amount of exhaust gases and at a high pressure and this must be released somewhere either in the atmosphere or right in the cylinders so that they can be burned so engineers decided to burn them right in the cylinders because venting it outside will be harmful to atmosphere so they are purged into the cylinders. Technically it is known as pcv positive crankcase ventilation where there are two hoses one is connected to the air box (after air filter) and the crankcase to get the crankcase fresh air and it's called breather hose the other hose called pcv is connected to the crankcase and the vacuum of the engine just after throttle body (moving from air filter) in case of a petrol engine.
Oil leak on the hose which came form valve cover to air intake
The leak starts after changing air filter
PCV (positive crankcase ventilation) valve is blowing by and causing engine oil to go through the PCV tube. I recommend replacing the PCV valve and clean out the tube. Then every time you have an oil change, I recommend replacing the PCV valve to prevent any more oil consumption and leakage. If you need further assistance with the oil getting on the air filter.
The positive crankcase ventilation (PCV) valve works to evacuate gas from the crankcase of the engine. The PCV valve directs these gases back into the combustion chambers via the intake manifold. This plays a large role in engine efficiency, improving emissions and the overall operation of your vehicle. A bad PCV valve will affect the performance of your vehicle, so there are a few signs to watch out for before the valve completely fails:
Symptoms of a Bad or Failing Positive Crankcase Ventilation (PCV) Valve
A bad PCV valve may have a leak, which will cause excessive oil consumption. In addition, you may also notice oil leaking through the seals and dripping on to the floor of your garage. This is because the pressure in the crankcase may increase when the PCV valve fails, so the oil is pushed out through the seals and gaskets since there's no other way for the pressure to be released. The leak will cause your vehicle to burn oil and leak oil beneath your vehicle. If you notice either of these, consult a professional mechanic to have your PCV valve replaced.
