ok..you can laugh at me..i'm no car genius but i have two mercedes that i love...i have a simple question i can't find in the old owner's manual...my wife has a great running 1989 300se w126....by the battery, there are two plastic bottles....one is fat and one is thinner and round, like a thermos...the big one is obviously the window washer fluid bottle ..what is the smaller thermos shaped bottle next to it..?..it has two small hoses running into the top.,.what is this bottle for..?..thanks..