Borg Warner Turbo 171702 on a Detroit engine

Many silicone coolant hoses are labeled " oil resistant " meaning they have resistance to oil due to their outer coating. They are not for oil flowing through them.
I prefer a hose like Gates TR500. Wire braided but light enough to still use hose clamps. Cummins uses or used a orange hose that looked like silicone but it is not.
The reason I mentioned this is because of a service call I did on an F Model Mack with a Cummins. It was rolling white smoke and had oil coming out of the turbo going to the engine air intake. I do not remember everything but it was close to the company shop and I was following orders. Pulled the VT50 turbo and rebuilt it at the shop. Put it back on and it made no difference. Then I was told it is the turbo. You did something wrong. Go take it off and bring it back. At that time I had done a lot of VT's and did not believe that. Started looking for other possibilities. When the turbo was removed I unscrewed the steel tube fitting from the turbo oil return brass elbow. There was an orange hose between the tube and a fitting going back to the sump. It looked like the hose I like but it was silicone. I doubt a pencil would have fit through the opening in the middle. Found a piece of garden hose handy and put it in place. No more smoke.
Long reply but that explains my belief and what is proper to the best of my understanding.

 

yeah now that you say this i have seen the same you dont see it from outside but hoses Can and do collapse on the inside Ive seen this on Fuel hoses as well Its mostly on hoses with Negative or 0 Pressure in them