I have oil coming into my air filter in my 1990 F1-50 ford truck?

I need someone give me lot of ideas what this might can be, I have a 1990 F 150 ford truck and its a 5.8 and I don't know why my oil coming from the top to the air filter making me lose lot of oil.

Hi because the oil breather pipe from the engines sump has lost it's valve.

Short of you putting oil in the air filter the only way it can get there's through the PVC system. If it is then your engine has a serious blow by problem and will not live much longer.

The crankcase breather is the reason. The problem is why is the breather doing this. Old engine blow by at the rings. Crankcase pressurisation. Engine near to worn out. Do a compression test.