No it's not that easy. Some cars don't show problems for a long time.
The problem comes from BMW making the cylinder walls out of nikasil which is eaten away by the high sulfur fuel that we have here. This is true for all E34 540's. BMW extended the warranty to 100k but in a lot of cases that's too early. And they have a hell of a time getting BMW to do warranty service beyond that (even at 105 or 110). Do some research on the web on the block numbers. DO NOT TAKE THE SELLER'S WORD FOR IT!!! This can prove way too expensive. There is a certain serial number range for the nikasil and alusil blocks. Do not buy a car with nikasil. If you are hellbent on it, then take it to a shop and have them do a compression and leak down tests. This is the first sign of a dying nikasil block (you won't really be able to feel anything while driving). But you'll see uneven compression.
As far as e34 vs e39, the e39 is a bit heavier I think but it is quite a bit stiffer and the engine has more torque (4.0 vs 4.4). I love my 535 but if I was choosing a 540 from e34 to e39, they're both equally a pain in the ass to service but the e39 is a newer and hence nicer car.
Originally posted by theblue
from my research I think that I should be OK because the car would have shown the problem before 126K miles. I prefer a higher mileage car in this case.
back to my main question (which was not reliability)
what are the motor codes of each 540i and what are the design difference etc???