Hi Lisa:
I think that Rob and Jim gave you good advice. If you don't know when the thermostat was replaced then go ahead and replace it. Peace of mind no matter what.

As Jim notes, the temp gauges on the 240s have a temperature compensation board that acts to "smooth out" the normal temperature fluctuations that normally occur (supposedly so as not to alarm us North Americans). At any rate, the board is notorious for problems that cause it to be either dead or to spike temps. You can try to clean off the mounting pins and remounting the board to see if that helps. I've just done that on mine, so I'll see how it works. I have usually done the "slap the dash" trick that was mentioned below; just one or two moderate slaps will usually result in good contact and the gauge will register OK. You can buy a new board (about $90 from the dealer, cheaper at some online parts dealers), or you can solder in a bypass wire and just have "real time" temp fluctuations (see here for directions on this: http://blarf.homeip.net/volvo/BB.cgi?forum=RWD&id=597712

As for your stalling problem, it is possible that the idle control system is not functioning properly. Do you notice that when you start it up you get a "fast idle" for a second or so and then it calms down (this is how it should be). If you haven't done this before, you should clean out the throttle body and then clean out the idle air control valve. This is not too difficult to do. As part of the brickboard there is the 700/900 FAQs, which gives repair tips for the 700/900 series cars. The 200 series cars have basically the same engines as the 700/900 cars, so you can look at engine repair tips there. Read about the idle air control valve here:

http://www.brickboard.com/FAQ/700-900/EnginePerformanceSymptoms.htm#Cold_Start_Dies_Dirty_IAC

See how to clean the throttle body here:

http://www.brickboard.com/FAQ/700-900/EnginePerformanceSymptoms.htm#PoorPerformanceIdleSurgeandHuntDirtyThrottleBody

Hope these tips help. If you are going to work on your car, the Bentley 240 manual that Jim mentions is a great resource. You can find them on eBay or on Half.com fairly inexpensively.

Hope this helps.

Mike
--
Mike Brown Greenville, NC 1996 965 113K 1994 940 135K 1986 244 137K