Volvospeed.com is a great resource for 850s. Swedishbricks.net also has a great deal of information (but more for 240/740 series). The main issue I have had on my '94 850 wagon has been a/c related. A very expensive fix so make sure to test it out if it's warm enough outside! Actually the problem with this model appears to be that it shuts off on very hot days after running for a while (15-20 minutes). I believe it's related to the a/c compressor clutch (?). Oil leaks can be minor or major (see thread on rear main seal)--try and have it checked out by an independent Volvo garage.