On an old 190D2.2, I had a leak that occured while I was out of town, away from a dealer. The car was still under warranty and after talking to the people at the 1-800 number, I bypassed it. I could not tell one bit of difference. This was in the dead of winter and I could not tell any difference at idle either. I guess it must have a purpose for being there but I sure could not tell what it was. Of course, since it was under warranty, I had it replaced but I would not have hesitated to leave it bypassed.