Cracked component in engine bay. Should I be worried? (PICS)

[Conquistador]

A friend of mine was poking around in my engine bay at the weekend and noticed this:

Apparently it shouldn't be a cause for concern any time soon but I may want to address it some time in the future. Anybody else noticed this on theirs or know exactly what it is??

 

[Sim_Simma]

I really can't tell what it is tbh but maybe someone with the same engine could help.

 

[GuidoK]

Replace it. It probably cost a quid or so.
Not fixing it can ultimately cause bad running, burnt valve seats (cilinder head refurb needed), or maybe even compensate your braking system.

 

[swanicyouth]

It's a vacuum cap. Replace it.

 

[Conquistador]

Replaced for the grand sum of £3 from my local indi. All sorted.