As noted above, this is a 1993 240 (a USA car)....
I've got an intermittant (about once every few weeks) problem in which my temperature gauge stops working (i.e., it reads stone cold) -- radiator and hose temperatures are normal. Fuel gauge continues to work correctly, though, so it's not the voltage stabilizer. Typically, after the cars sits awhile and I restart it, the gauge then works normally, as if nothing was ever wrong, and this won't happen again for a few weeks to a few months (unpredictable).

I'm figuring that, most likely, the connection to the temperature sensor in the block is unreliable (probably has to be cleaned, tightened). But where is it? I'd appreciate a description of the location.

In advance, thanks!