I had a broken return line on the diesel injectors in my Alfa 159.
I estimate from the fuel-gauge I lost about 15 liter of diesel in total during the 20 km or so I drove with the car after the leak started. (In hindsight I can pinpoint the moment the break happened exactly.)
The workshop replaced the lines (all four) and the leak is gone.
But on the way home after about 10 minutes (when the engine got hot) I stopped for a traffic light and I saw grey smoke coming from under the hood and out of the front wheel arches.
I found they replaced the lines but didn't do a good job on cleaning up the diesel that sprayed around the engine block. It's basically everywhere in the engine bay. So when things get hot the diesel residue starts smoking.
If it had been petrol my car would probably already be in flames... Luckily diesel has a much higher flashpoint.
I can 't get back to the workshop, or any other workshop, due to the Pentecost long weekend. Everything is closed. But I do need my car this weekend and Tuesday to get to work. (Murphy's Law: Important meeting in early morning that I just can't miss. And public transport is non-existent in that area.)
I don't mind riding a smoking car until the diesel-residue has evaporated, but I'm a bit worried about fire-hazard and also about the diesel possibly eating away at plastic/rubber in the engine bay.