I haven't replaced a radiator in an 850 (yet) but there are others on this board who have. A search might locate a post with useful tips. The thermostat is an easy job. You'll just need access to the rear bolt on the housing. Here's the link to Bay 13. Bookmark it in your browser!

http://www.volvospeed.com/maintence.htm

Click "Engine" and you'll find the thermostat and ECT sensor replacement procedure.

The rattle & clunk (U2?) you're hearing from the front right is probably a broken strut mount. Common ailment. Can also be a DIY but might want to find an independent Volvo shop to handle some of the stuff you're not comfortable with. There are several components that can cause all types of unusual noises from the front suspension. Try and identify when and under what conditions you hear the noise. Easy enough to jack the car up, pull the wheel off and have a look. Front wheel hub bearings will groan or rumble on the corner opposite the direction you're turning, ball joints, control arm bushings and sway bar end links are all items to check over, or start saving for at 100k.

Top radiator hose is easy, bottom one is not, but probably ok once the radiator is removed.

Crankshaft rear seals are known for seepage problems at your mileage. Replacement of course is expensive (labor). I lucked out (in a way) and discovered my car had a transmission replacement 25k ago and the rear seal was done then.

I could go on but again, using the search function of this site will uncover lots of information. I've been away from the list for a month or so and am surprised at all the "new" users. They're asking the same questions all over again.

I believe these are good cars but they, like any others, have their weaknesses. You rarely see people search out a site like this just to say they have no problems. With that in mind, I'd say the vast majority of 850s are very reliable.

Regards,

--
Erwin in Memphis, '95 855t