What's that little cap with an H on it?

[RedM]

I have been told before but I can't remember. Tried a search but can't find any mention of it!

So yeah, the little cap with an H on it. Located right at the front of the engine bay, in the centre. It has a little 'window' next to it that you look down into. What should be visible in that window?

Thank you.

[absxxxx]

its for your aircon system , high pressure side :cool:

[RedM]

Cheers.

Should anything be visible in that little window?

[peter richards]

nude women :nyah:

[smarty]

I think you should see some little bubbles through it when the air con is on.