A simple thing is, when driving diesel is let the engine running idle for at least 30s before switching off. The oil which will be too hot have the chance to cool down and don't clog the turbo and other bits. Not necessarily the faulty could be avoided if you're driving the way diesel engines "like" (motorway, long runs). If the previous owner abused from short runs, possibly the problem was just a matter of time. Just don't get upset. As engines get more efficient and more powerful, they tend to get way more complex and that's the reason we should keep a closer look and pay attention to many things. It is necessary in all modern cars, but not a big deal for RCZ owners who already love the car from bumper to bumper, hahaha. In my case was quite easy to monitor many things as I used to clean the engine bay every 2 or 3 weeks, lol.