what is this breather tube on a 103?

[Stringer]

I recently saw this photo posted on another forum and spotted a breather tube stretching from one side (near the fuel distributor) all the way round to the other side and disappearing somewhere near the battery.

I have two questions for mbclub. 1. What is this tube? 2. Is there a comprehensive diagram on the site which shows all breather tubes for the 103 (300e) engine?

thank in advance

m in beirut

 

[mct_cars]

Just a guess, but as it's going from the manifold through the bulkhead, is it vacuum for the economy guage?

 

[Stringer]

i'm baffled. But here's another conundrum if you like them on sunday mornings. I was thinking of disconnecting my coolant temp sensor as i have suspected for a long time that it is 'stuck' on high resisitance (i.e permanently telling the cold valve start to stay rich). However, this morning, fate played a role in my disconnecting it as i managed to bugger up one of the terminals which just crumbled off. So, here's my question. If i drive around with an 'open' circuit the rich setting will be on permanently, right? But what if i connected the two cables and made it no resistance? Shouldn't this set the CSV to close and make it run lean? Help,,,