[UvjqTVVC]

I know there are a few mechanicy types on here, who will hopefully have been drawn out of hiding by ace_rimmer's post, so here's my problem: overheating!

It's only been the last couple of days or so, but after driving for only 10 minutes or so, my temperature guage goes right up to between 75% and 100%. It normally stays there, but today after I went through the McDonald's drive through and had to turn the engine off and back on, it went right up to 100% and my big red "STOP" light came on. When I drive slowly, like through towns, it seems to cool down a bit, and when I was going down a big hill with my foot entirely off the accelerator the warning light went off and it cooled down a fair bit.

I checked my water level yesterday (the tube next to the radiator) and it was pretty much empty, so I filled it back up with water (apparently I should have used anti-freeze. Oops!). That didn't seem to make any difference. From reading into it it seems that maybe the thermostat is at fault. Does that sound about right? I suppose I'll have to take it to the garage to get it fixed, just wondering if the symptoms seem exactly like anything anyone's heard of or experienced. Ta!