I have a hose which connects to the radiator expansion tank, actually just under the pressure valve/cap. I noticed recently that the hose (which has a kind of mesh weave around it) had split, obvious signs were that it was old and brittle.
Upon further inspection and after a visit to MB spare parts I noticed that the hose did not follow the MB diagram supplied, It kind of ran under the expansion tank and along near the indicator and then disappeared through what looked like a dedicated hole made for such a hose, at the time I couldn't get under the car so I left it and rebuild it back to normal.
My question is this, what is this hose, where does it go and why can I run and drive the car with no apparent consequences or implications, if the system is under high pressure why do I not see steam emitting from the now open nipple that used to have a hose fitted.
I have added some images, please help.

Thanks.

 

Cool, so basically no requirement for this ludicrous over design and route and I can replace it with a cheaper alternative.