My TD5 has only done 380 000 km to date, but it is now 12 years old. It did a head gasket and had very bent plastic dowels (z shaped!) when we did the head at just on 120 000 km 3 years in. Luckily the valves had not rubbed on the bore!
Since then I have done the fuel pressure regulator and currently have a leaking fuel cooler (I have the O-rings but it’s one of them O round-to-it jobs) and an oil leak. Heading to the Cape later this year so will see if we crack 400 000 km.

