The 3 litre Patrols of that Vintage are the ones that started the ZD30 hand grenade stories. That said, my Dad has one that has never missed a beat and I put 140 000 km on a 2001 with no issue. From all reports, most of the bugs were ironed out by about 2006 but there are ways to make the earlier versions more reliable and due to their reputation they are cheap to buy. All the 3 litre diesels are intercooled turbos. Both the 4.5 and the 4.8 are typical of big petrol engines in big 4wd's - go like stink but drink harder than an NRL player on mad Monday. The 4.2 litre turbo diesel is the cream of the crop as far as being rock solid is concerned but hold their value to a much greater extent if you can find one. There are some good forums on the Patrols - good places to do research