2013FSport

iTrader: (2)

Yes. The tube is essential and it must be near the bottom. And it will be connected to the cap vent under the cap.

On a full block most often the fluid expands but never violates the caps pressure rating. However, air in the system can turn to steam and when this happens, often times it does exceed the caps rating and vent to the reservoir.

If the reservoir is full and has a hose to the bottom, as the engine cools the fluid contracts forming a vacuum on the engine block side. The cap has a one way valve that opens and pulls fluid from the reservoir thus filling the block on the cool down cycle.

I tiny leak in the system can render this process inoperable.

MikeFig82

iTrader: (13)

Ok it' been weeks, and so far so good not even pink crust on the cap of the resevoir. If you are haveing pink build up. I would suggest you bleed the coolant system. To unsure you have no air trapped in the system.