I have all new PVC /oil separator, vacuum hose lines and i have vacuum at intake.BUT I have no vacuum at oil filler neck.I thought i need same vacuum to keep oil in,yes ???????

 

No vacuum there and it appears that you have excessive blow by and are blowing the oil out the exhaust. If you replaced the oil separator and still are getting this cap leak it looks like the rings are on their way out. How much oil are you losing. We didn't get an answer here so is it a quart every 500 miles or what?

 

about 100 to 200 mile it can be 1/2qt to 2.5qt.yes .5 to 2.5 but then it could be 0. i am pulling my hair out