I've had three Patrols, the first was a 3.3D Y60, straight six, gear driven cam so no belt issues, I put 100K on it, 250K when I sold it, briliant basic truck, excellent off road, there was literally nothing that stoped it..
The 4.2 was very good as well, strong and reliable and very capable, I only sold it due to needing LWB.
The last was 2001 3.0tdi which I pimped for the Macmillian UK 4x4 Challenge in 2008. Lifted +2" with Old Man Emu parts, Dastek chip, raised air intake & breathers etc. Nice truck to drive, very capable, quite luxurious. The heads are known to go at around 80K+ (mine did!). Unfortunately it got hit by an HGV when he lost the trailer unit on a bend and it got written off. I couldn't believe how much rust was exposed due to the accident, all on the inner of the panels. I always stayed away from the 2.8's as they were a little underpowered and a couple of friends had head gasket issues. The newer models don't seem to have the same build quality as the older ones.
Your'e unlikley to find any 3.3's around now in good condition but I would certainly recommend the mid to late 90's 4.2. I'd also recommend a Toyota Landcruiser 4.2 VX 80's series (then became 100 series), fantastic engines, the only thing you need to check is if the bottom end bearings have been replaced. Relatively easy job to have done as it can be done with engine in situ (it's a lorry engine really). 3 diff locks, loads of torque, great cruiser for long journeys and not too bad on fuel.
