Actually IMO even the newer Mercedes have less-than-optimal recirculation as it automatically turns off after some time. In my MB I end up pressing that button many times each day. It seems that MB has always thought drivers are too dumb to regulate their own recirculation. In other cars you just press the button and it stays there and I think that's a much better system. If some drivers are too dumb to let in some oxygen once in a while, that's their problem IMO.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL