Identify this part?

[ericbikes]

Hi- I have E39 and I get loud hissing left side of engine coming from bottom hose of this silver part that looks like some kind of vacuum part. Can someone pls identify? The loud leak sounding noise stops after about 60 seconds of starting cold engine and does not happen starting warm engine. Never happened before.

[Emilime75]

You do realize that this forum is for a different chassis and generation of BMW, right?

Try here https://e39.5post.com/forums/

[hans_e39_530i]

First, answering Emilime75, I don't know what are you complaining about, since the picture is clearly from a post-facelift, probably MY 2002 BMW e39.
The valve in question is called Secondary Air Injection Valve. The BMW part number is 11727540468
This is the EGR valve. It is pneumatically actuated and so, when starting, it should make some hissing sounds if it is still emptying the air in the accumulator. After the vaccum pressure is achieved, it should really stop.
If i recall correctly, the EGR opens in the high load area of the engine map, so that the temperature in the combustion chamber is reduced, say, from 750C to 400C. This happens because the EGR lets exhaust gases in the combustion chamber and so, reduces oxygen concentration. The reduced temperature reduces the formation of poisonous NO2 (the Nitrogen from the air ends up oxidized in high temperature).

[Emilime75]

Originally Posted by hans_e39_530i

First, answering Emilime75, I don't know what are you complaining about, since the picture is clearly from a post-facelift, probably MY 2002 BMW e39.

This was originally posted in the E90 section. I was merely letting the OP know that there was a better place for his question. It was since moved over here. Carry on.

[hans_e39_530i]

Originally Posted by Emilime75

This was originally posted in the E90 section. I was merely letting the OP know that there was a better place for his question. It was since moved over here. Carry on.

ok, I didn't guess that. As an owner of another post-facelift e39, I am sometimes annoyed because most of the internet only cares about the pre-facelift models, I thought that was also the case

Hans