Thanks for all the tips guys, it's funny how no one seems to like these vehicles and claim horrible reliability...
He did have the head of the motor re-done. See attached.
Reliability as everything to do with maintainability on a Discovery 2. Since they are old, how well they have been maintained is the question. $10k for a D2 that doesn't have at most 30k miles on it and the plastic covering the seats when it is was new is ridiculous. My 1999 with full records and 90k on the clock with 2" OME lift was $5500 almost 4 years ago AND I paid $1k over market value because I liked that the receipts showed Great Basin Rovers did the work.
After that you MUST do the following:
1) TD5 thermostat, which is 180F, it lowers temps and reduces the chance of a slipped liner/overheat. (that's minimal generally you are looking at an entire cooling rebuild) $50-600 depending on extend of cooling system refresh.
2) Servicable driveshaft ($350 or take yours to a reputable rebuild shop). Don't forget a servicable centering ball. The heat from the CATs dries out the sealed grease in the U-joints and anywhere between 100k and 150k miles the driveshaft siezes and blows up....usually punching a huge hole in your transmission... So now you have to grease this driveshaft every 3k miles with high-temp grease. Easy, but it MUST be done.
3) OBD2 reader such as a scanguage or ultraguage. Why? Because the stock D2 temp. guage only moves off of middle after you are in the DANGER ZONE and pretty much already hosed for a head-gasket failure. Read the temps in realtime. Usually below 205 is good. I'm around 200F in 4-lo in Moab crawling in ambient temps in the triple digits. Usually I'm around 188-194. Much better than the 220F it registered BEFORE the TD5 thermostat mod.....no wonder the PO spent $2k on a head gasket/head refurb. job.
After that there are little things such as checking the rotoflex and change as neccessary, making sure you use a flat-tappet friendly oil such as Rotella Synthetic 5w40, and you are good to go.
I've put 20k hard miles on my disco 2 and it has been by far the most reliable 4wd I've owned *knock on wood*. But even then, I'm waiting for the inevitable day I slip a liner. Oh well, there are so many awesome 4wds in the world, I'll just move on to the next project at that point.
There are MANY people around that have Disco 2s and especially 1s with at or well over 200k miles.
But please don't pay $10k for one..
