Hey Randall,
That's also a sign of a failed oil/air separator. When it fails, it creates a big vacuum on that tube so it pinches down when the engine is revved and eventually cracks it.
Also, if you can get him to replace your clamps on the oil filler tube with good, stainless screw downs, you can remove the clamp from the top in the future. That makes the oil filler tube a 30 minute job from above rather than a 2 hr job from below.
