Mopar's Notes: Here is the result of leaving the stock crankcase vent in place and the problems it causes like overheating... Here is the story from Edcasey from Cummins forum at Should of lost my puke bottle a long ago
I finally got around to doing Mopar1973Man's mod for the puke bottle. I knew I needed to clean my radiator even before this happened. My truck ran hot (215 - 220 degrees) in stop and go traffic or when towing my 3000 pound trailer. Also, at idle, my air conditioner barely worked. It all pointed to an air flow problem.
So I pulled the radiator and I would say this is an air flow problem:
So I used some degreaser and my power washer to clean everything.
So once that was done I went to work on the new vent setup. It's Mike's design just plumbed slightly different (probably still a patent infringement).
While I had it all apart, I flushed the cooling system and changed the thermostat. When it was back together I took it for a test drive. It heated up to 190 degrees much faster than before thanks to the new thermostat. When the thermostat opened it actually dropped down to about 185 degrees. I've driven this truck daily for about 4 years and it has never done that. I decided to take it for a ride through the city. I spent 45 minutes in stop and go traffic with the air conditioner on and it never went above 190 degrees. Before it would have gone to about 215. It was definitely worth the time it took and I should have done it a long time ago.
The down pipe I kept short enough that road debris will not strike the downpipe as well as keeping up near the engine heat in hopes to keep it from freezing shut. Take notice the steep angle cut on the end of the pipe added to keep the tip from possibly freezing shut as well.