Diesel engine for use inside the city

Hello guys,

I would like to ask you about the use of a diesel engine car in the city. I know
everything there is to know about the euro5 and euro6 classification and the
supposed ban of them inside the big cities but I am not worried about that.

What I want to know is something about the engine and its use in the city. I
have found a used car I really want to buy and I am very close to doing it, it
is a bmw, 2016 model with a euro 6 engine. The thing is that yesterday I
went to a service spot for my other car and I asked the mechanic’s opinion
about the car I want to buy. He told me that he wouldn’t buy a diesel car for
the city and that the only way to correctly use a diesel engine is if you travel
a lot or have a cab. His theory was that when you use a diesel engine for the
city, it means that you use it for small amounts of time and then it remains
inactive for the rest of the day and this is bad because the brain of the
engine doesn’t have the time it needs to burn the diesel and this damages
the engine. He told me some other technical things too but I really lost him
after that. Is this correct?

Many people I know drive diesel cars inside the city and use them like I
would but I have never ever heard them complain about this type of problem.

Does this really happen or was it just a wrong opinion? Does someone here
own a diesel car that he uses just for the city commute?

Thank you