Small air space in coolant reservoir

[QUICKSILVER462]

"If the hose just connect to the bottom of the reservoir, will it be better?"
If the overflow hose from the radiator was positioned at the very bottom of the overflow tank, any "crud" (dirt, corrosion, gloop) that settles out from the coolant will find it's way back into the radiator, and could possibly clog the overflow bottle hole/hose.

[Coldwaves]

"If the hose just connect to the bottom of the reservoir, will it be better?"
If the overflow hose from the radiator was positioned at the very bottom of the overflow tank, any "crud" (dirt, corrosion, gloop) that settles out from the coolant will find it's way back into the radiator, and could possibly clog the overflow bottle hole/hose.

Good point. This totally make sense. I do notice there are some dirt precipitate on the bottom of the bottle. So Putting it sideway instead of bottom can avoid this problem.

But what is the purpose of making a U bend instead of just having the hose connect to the side wall? Hope you have another genius explanation