The same person who designed the 240 heater core, designed the placement of the AC evaporator. It a 10 hour book job to replace. This is true for any FWD Volvo.
What not to buy: 1993 850, 1999-2001 S80. Stay away from 2001 in general.
Tha early AWD were mechanical and costly to repair, the bevel gear tended to break if not cared for (lubed for life?).

The 1984-5 850 still had OBD boxes in the engine compartment, 1996+ cars require a scanner.
1999 was the first year for electronic throttle. The factory warranty has expired (10 years/200k miles). A Canadian outfit repairs them.
The turbo is extremely robust, it matches the white block in longevity.
The seatbelt rubs against the seat bolster, wearing off the leather(?).
The electronic climate control is the best in the industry.

Klaus
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I am not a mechanic, so can you trust what I type?