I am still learning about this SL I recent bought. I was wondering if anyone could tell me what tank is mounted next to the radiator that has a braided line to it and a vacuum line to it. It's on the driver's side of the radiator and is almost as tall as the rad.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member