2005 chevy silverado coolant overflow bottle question.?

[d s]

Hi on my silverado 2005, I often smell coolant at idle when the engine is hot, none of the hoses are leaking or compromised. However the coolant overflow bottle, has a nipple on side near the top with a corrugated tube that actually looks like loom, this then vents to atmosphere. This is a new vehicle for me and I am not familiar with this type of layout. Is this normal or did someone monkey something. If so if anyone has a coolant system diagram it would be of much help.

Thanks a bunch!

 

[tinsink5]

when you are stop at and idle is the fluid coming out of the over flow have you checked