That breather setup is NG if in a cold climate! Condensation will build up at the point of where it can collect and freeze when cold enough. Engine heat is not a savior here as most of the water vapor begins to collect as the engine is warming up and short trips will produce a ton. A frozen shut vent WILL pop your tappet cover gasket.

(This is why even when doing it under the truck to have zero undulations AND any "uphill" bends in your hose)

I did mine 9 years ago and it has kept the inside framerail down by the transfer case rust free ... Move over Rusty Jones theese trucks Make their own rust proofing.