the bently doesn't have much info on the m60 radiator...
do you have an auto or manual tranny? The auto tranny might have some kind of cooling thing... but I drive a manual so thats just a guess..
check out http://rust.mine.nu/bmw/carselect.do and narrow it down to your car, there are a lot of good diagrams, you might be able to figure out what your looking for.
I replaced the radiator in my 530iM a couple of months ago, pretty easy to replace, but the radiator was 200 bones at bma (going with the one patrick suggested).
If you do replace the radiator, be sure to get 2 replacement radiator clips (they hold the radiator down). the plastic gets real brittle and will probably break when removing the radiator.
Former: 95-530iM
Current: 99 GMC Seirra 1500