W204 hose identification

[glenluceblue]

Hi,
Can anyone tell me what this hose is for in my 2009 C220 cdi? I think it may be related to the EGR but I am away from home just now so cannot trace it myself.
If anyone has a part number and also information on whether this is a straightforward job to replace, i.e DIY, it would be very much appreciated.
Cheers

 

[glenluceblue]

Can anyone help with this query?
Thanks

 

[star]

It’s a heater hose.

 

[glenluceblue]

Cheers for that