I’m thinking of buying a 2017 Isuzu D-max LS-U, but some people told me that it's not good for short distances because something or other doesn’t get to burn. I'm no car expert and I would only drive the car for about 10 min to and from work Monday to Friday. Apparently it needs to run above 70 km/h for 20 min for something to burn. Is this true?
What they were referring to is the automatic burn of the Diesel Particulate Filter (DPF), which collects carbon in the exhaust while you are driving along, and then periodically goes through a cleaning process in which the accumulated carbon is burnt off. The burn-off happens automatically without you knowing it’s happening, but it needs regular freeway type driving for it to happen. If your travels don’t involve any freeway travel then the burn-off might not happen and you have to take it to a dealer to have it done manually. From what you tell us about your driving I would say it doesn’t suit a diesel, and you would be better off buying a car with a small petrol engine.