Black smoke loss of power W210 320 CDi

[tenerifepaul]

I was pulling my caravan at the weekend when all of a sudden I lost all acceleration power. When I was up to cruising speed @ 2000rpm everything seemed OK.I noticed when trying to accelerate there were copious amounts of black smoke being produced. Upon inspecting underneath the bonnet the next day I noticed that the indicaticator on the air box was red. I turned it back to white and every thing seems OK. Does anyone know what could have caused the problem?

 

[hmang]

always wondered ...what does that indicator actually do ? apart from get stuck.

 

[Ron Palfrey]

Clutch slipping?