Valve Stem at front left of Engine Compartment

[robwat]

Hi, general query here, not related to any fault, just curious. Looking at the engine of my 2000/W S3, I noticed a small screw cap which i undone. It was covering a tyre type valve which when pressed released air. What is this for? If there is a lot of air coming out when pressing, does this indicate a problem? Any more info much appreciated.

[MickCheese]

Is it for refilling the air con?

[chris g]

hi.i think you will find it is for charging your air con

[SEMKY]

Yep, this is the charging connection for the air conditioning refrigerant gas. The 'air' released from here should actually be refrigerant gas.