There are circumstances under which you would stay away from a modern turbo-diesel, but they have more to do with how you’ll use the vehicle than they do with the vehicle itself. The rule of thumb is that you should really only buy a diesel version of a particular car if you plan to use it for at least one decent trip at freeway speeds every three or four weeks at the very least. Along with that is the proviso that you’ll cover enough kilometres each year to balance the higher purchase price and servicing costs of a diesel against the lower fuel costs.
The highway-driving caveat is all about long-term reliability and emissions. Modern turbo-diesels are often fitted with what’s called a diesel-particulate filter (DPF). This filter, designed to trap some of the more harmful exhaust emissions) eventually fills up with the soot from the diesel’s exhaust and, when that happens, it’s designed to burn off that soot and regenerate itself, ready for another go round. But if you only drive short distances or only ever at suburban speeds, the filter can often not get hot enough to perform this burn-off and regeneration. When that happens, the filter warning light on your dashboard lights up and it’s off to the dealership for a – sometimes – costly manual regeneration. In extreme cases, the DPF may even need to be replaced and that’s not cheap either.
So, if you’re not planning regular trips at freeway speeds, conventional wisdom says a modern turbo-diesel is not for you.