Overall great cars but they have some quirks, a couple of which can cost you mega$$$$$$. The 850 has no transmission filter and had no recomendation from volvo on changing the fluid so there are plenty of them around with the origional factory fluid still in ( not good). Ask for the service records and look for ATF change info plus pull a small sample and have a look. If it looks like rancid chocolate milk, reject it. The flame trap needs to have be serviced on a regular basis but is a pain to get to on the 850 so it is often passed up leading to a mega$$$$$ blown rear engine seal repair. The A/C evaporator failure is well documented. Repair $1000.+ SOme folks report a lot of small but annoying electrical gremlins. Ours has been a great car w/o major problems. Haynes prints a fair manual for them

bl