What is this part please

[onwards]

Untitled

• onwards
• 6 Dec 2009
• 1

The black plastic screw is loose and as you can see there's a bit of corrosion. Should I replace it. If so what do I ask for...

Thanks....

 

[seco services]

its an auto air vent should let air out but not water.

 

[geezer466]

Read my problem couple of threads down.. Wish I had one of these would solve my problem.

 

[Whitespirit66]

Looks like its been emitting water, which it shouldn't. If your system is dirty, it can cause it to jam.