1999 BMW 328 Anti-freeze Leak

That is the bleeder valve. It is available separately and take care when you tighten it, it is made of plastic and can be easily over tightened.

Thank you so much!! Do you know what may caused it to leak anti-freeze from there? And also do I have to purchase that part from the dealer or can I get it from the auto part store?

The plastic can and does often split and may require replacement of the expansion tank and these are usually not something they have on the shelf at Pep Boys. There are several on-line BMW suppliers, check them out.

thanks again.. is this part hard to replace and will it harm my car if I drive it until I get the part?

Not hard to fix at all, but I would not take the chance of overheating the car. Get this fixed ASAP.

Replacing it its not hard. If you drove your car with that you might get more problem that is hard to fix.